split up traversal so it's easier to maintain and extend later on
This commit is contained in:
Sebastian McKenzie
parent
b8f8f24e82
commit
beb5ccab25
78
lib/6to5/traversal/context.js
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78
lib/6to5/traversal/context.js
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@ -0,0 +1,78 @@
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"use strict";
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/* jshint maxparams:7 */
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module.exports = TraversalContext;
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var TraversalIteration = require("./iteration");
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var flatten = require("lodash/array/flatten");
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var compact = require("lodash/array/compact");
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function TraversalContext(scope, opts, state) {
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this.shouldFlatten = false;
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this.scope = scope;
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this.state = state;
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this.opts = opts;
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this.reset();
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}
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TraversalContext.prototype.flatten = function () {
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this.shouldFlatten = true;
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};
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TraversalContext.prototype.remove = function () {
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this.shouldRemove = true;
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this.shouldSkip = true;
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};
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TraversalContext.prototype.skip = function () {
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this.shouldSkip = true;
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};
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TraversalContext.prototype.stop = function () {
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this.shouldStop = true;
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this.shouldSkip = true;
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};
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TraversalContext.prototype.reset = function () {
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this.shouldRemove = false;
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this.shouldSkip = false;
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this.shouldStop = false;
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};
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TraversalContext.prototype.visitNode = function (node, obj, key) {
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this.reset();
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var iteration = new TraversalIteration(this, node, obj, key);
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return iteration.visit();
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};
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TraversalContext.prototype.visit = function (node, key) {
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var nodes = node[key];
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if (!nodes) return;
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if (!Array.isArray(nodes)) {
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return this.visitNode(node, node, key);
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}
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// nothing to traverse!
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if (nodes.length === 0) {
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return;
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}
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for (var i = 0; i < nodes.length; i++) {
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if (nodes[i] && this.visitNode(node, nodes, i)) {
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return true;
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}
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}
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if (this.shouldFlatten) {
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node[key] = flatten(node[key]);
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if (key === "body") {
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// we can safely compact this
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node[key] = compact(node[key]);
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}
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}
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};
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@ -2,174 +2,9 @@
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module.exports = traverse;
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/* jshint maxparams:7 */
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var Scope = require("./scope");
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var t = require("../types");
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var contains = require("lodash/collection/contains");
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var flatten = require("lodash/array/flatten");
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var compact = require("lodash/array/compact");
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function TraversalContext(scope) {
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this.shouldFlatten = false;
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this.shouldRemove = false;
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this.shouldSkip = false;
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this.shouldStop = false;
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this.scope = scope;
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}
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TraversalContext.prototype.flatten = function () {
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this.shouldFlatten = true;
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};
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TraversalContext.prototype.remove = function () {
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this.shouldRemove = true;
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this.shouldSkip = true;
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};
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TraversalContext.prototype.skip = function () {
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this.shouldSkip = true;
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};
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TraversalContext.prototype.stop = function () {
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this.shouldStop = true;
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this.shouldSkip = true;
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};
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TraversalContext.prototype.reset = function () {
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this.shouldRemove = false;
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this.shouldSkip = false;
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this.shouldStop = false;
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};
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TraversalContext.prototype.maybeRemove = function (obj, key) {
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if (this.shouldRemove) {
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obj[key] = null;
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this.flatten();
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}
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};
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TraversalContext.prototype.replaceNode = function (obj, key, node, replacement, scope) {
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var isArray = Array.isArray(replacement);
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// inherit comments from original node to the first replacement node
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var inheritTo = replacement;
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if (isArray) inheritTo = replacement[0];
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if (inheritTo) t.inheritsComments(inheritTo, node);
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// replace the node
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obj[key] = replacement;
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var file = this.scope && this.scope.file;
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if (file) {
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if (isArray) {
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for (var i = 0; i < replacement.length; i++) {
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file.checkNode(replacement[i], scope);
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}
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} else {
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file.checkNode(replacement, scope);
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}
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}
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// we're replacing a statement or block node with an array of statements so we better
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// ensure that it's a block
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if (isArray && contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
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t.ensureBlock(obj, key);
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}
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if (isArray) {
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this.flatten();
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}
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};
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TraversalContext.prototype.call = function (fn, obj, key, node, parent, scope, state) {
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var replacement = fn(node, parent, scope, this, state);
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if (replacement) {
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this.replaceNode(obj, key, node, replacement, scope);
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node = replacement;
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}
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this.maybeRemove(obj, key);
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return node;
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};
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TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent, state) {
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this.reset();
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var node = obj[key];
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// type is blacklisted
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if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) {
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return;
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}
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var ourScope = scope;
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// we're entering a new scope so let's construct it!
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if (!opts.noScope && t.isScope(node)) {
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ourScope = new Scope(node, parent, scope);
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}
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node = this.call(opts.enter, obj, key, node, parent, ourScope, state);
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if (this.shouldSkip) {
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return this.shouldStop;
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}
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if (Array.isArray(node)) {
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// traverse over these replacement nodes we purposely don't call exitNode
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// as the original node has been destroyed
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for (var i = 0; i < node.length; i++) {
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traverseNode(node[i], opts, ourScope, state);
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}
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} else {
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traverseNode(node, opts, ourScope, state);
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this.call(opts.exit, obj, key, node, parent, ourScope, state);
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}
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return this.shouldStop;
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};
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TraversalContext.prototype.visit = function (node, key, opts, scope, state) {
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var nodes = node[key];
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if (!nodes) return;
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if (!Array.isArray(nodes)) {
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return this.visitNode(node, key, opts, scope, node, state);
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}
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if (nodes.length === 0) {
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return;
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}
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for (var i = 0; i < nodes.length; i++) {
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if (nodes[i] && this.visitNode(nodes, i, opts, scope, node, state)) {
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return true;
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}
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}
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if (this.shouldFlatten) {
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node[key] = flatten(node[key]);
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if (key === "body") {
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// we can safely compact this
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node[key] = compact(node[key]);
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}
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}
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};
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function traverseNode(node, opts, scope, state) {
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var keys = t.VISITOR_KEYS[node.type];
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if (!keys) return;
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var context = new TraversalContext(scope);
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for (var i = 0; i < keys.length; i++) {
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if (context.visit(node, keys[i], opts, scope, state)) {
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return;
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}
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}
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}
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var TraversalContext = require("./context");
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var contains = require("lodash/collection/contains");
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var t = require("../types");
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function traverse(parent, opts, scope, state) {
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if (!parent) return;
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@ -187,13 +22,25 @@ function traverse(parent, opts, scope, state) {
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// array of nodes
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if (Array.isArray(parent)) {
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for (var i = 0; i < parent.length; i++) {
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traverseNode(parent[i], opts, scope, state);
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traverse.node(parent[i], opts, scope, state);
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}
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} else {
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traverseNode(parent, opts, scope, state);
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traverse.node(parent, opts, scope, state);
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}
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}
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traverse.node = function (node, opts, scope, state) {
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var keys = t.VISITOR_KEYS[node.type];
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if (!keys) return;
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var context = new TraversalContext(scope, opts, state);
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for (var i = 0; i < keys.length; i++) {
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if (context.visit(node, keys[i])) {
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return;
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}
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}
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};
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function clearNode(node) {
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node._declarations = null;
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node.extendedRange = null;
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126
lib/6to5/traversal/iteration.js
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126
lib/6to5/traversal/iteration.js
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@ -0,0 +1,126 @@
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"use strict";
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module.exports = TraversalIteration;
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/* jshint maxparams:7 */
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var traverse = require("./index");
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var contains = require("lodash/collection/contains");
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var Scope = require("./scope");
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var t = require("../types");
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function TraversalIteration(context, parent, obj, key) {
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this.key = key;
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this.obj = obj;
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this.context = context;
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this.parent = parent;
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this.scope = TraversalIteration.getScope(this.getNode(), parent, context.scope);
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this.state = context.state;
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}
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TraversalIteration.getScope = function (node, parent, scope) {
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var ourScope = scope;
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// we're entering a new scope so let's construct it!
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if (t.isScope(node)) {
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ourScope = new Scope(node, parent, scope);
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}
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return ourScope;
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};
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TraversalIteration.prototype.maybeRemove = function () {
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if (this.context.shouldRemove) {
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this.setNode(null);
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this.context.flatten();
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}
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};
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TraversalIteration.prototype.setNode = function (val) {
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return this.obj[this.key] = val;
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};
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TraversalIteration.prototype.getNode = function () {
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return this.obj[this.key];
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};
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TraversalIteration.prototype.replaceNode = function (replacement, scope) {
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var isArray = Array.isArray(replacement);
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// inherit comments from original node to the first replacement node
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var inheritTo = replacement;
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if (isArray) inheritTo = replacement[0];
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if (inheritTo) t.inheritsComments(inheritTo, this.getNode());
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// replace the node
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this.setNode(replacement);
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var file = this.scope && this.scope.file;
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if (file) {
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if (isArray) {
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for (var i = 0; i < replacement.length; i++) {
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file.checkNode(replacement[i], scope);
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}
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} else {
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file.checkNode(replacement, scope);
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}
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}
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// we're replacing a statement or block node with an array of statements so we better
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// ensure that it's a block
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if (isArray) {
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if (contains(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.obj)) {
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t.ensureBlock(this.obj, this.key);
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}
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this.context.flatten();
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}
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};
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TraversalIteration.prototype.call = function (fn) {
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var node = this.getNode();
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var replacement = fn.call(this, node, this.parent, this.scope, this.context, this.state);
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if (replacement) {
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this.replaceNode(replacement);
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node = replacement;
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}
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this.maybeRemove();
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return node;
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};
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TraversalIteration.prototype.visit = function () {
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this.context.reset();
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var state = this.context.state;
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var opts = this.context.opts;
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var node = this.getNode();
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// type is blacklisted
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if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) {
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return;
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}
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this.call(opts.enter);
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if (this.context.shouldSkip) {
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return this.context.shouldStop;
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}
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node = this.getNode();
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if (Array.isArray(node)) {
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// traverse over these replacement nodes we purposely don't call exitNode
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// as the original node has been destroyed
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for (var i = 0; i < node.length; i++) {
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traverse.node(node[i], opts, this.scope, state);
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}
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} else {
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traverse.node(node, opts, this.scope, state);
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this.call(opts.exit);
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}
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return this.context.shouldStop;
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};
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