babel/lib/6to5/transformers/block-binding.js

98 lines
2.2 KiB
JavaScript

var traverse = require("../traverse");
var util = require("../util");
var b = require("ast-types").builders;
var _ = require("lodash");
var isLet = function (node) {
if (node && node.type === "VariableDeclaration" && node.kind === "let") {
node.kind = "var";
node._ignoreBlockBindingHoist = true;
return true;
}
};
var hasLet = function (nodes) {
var has = false;
_.each(nodes, function (node) {
if (isLet(node)) has = true;
});
return has;
};
exports.Program = function (node) {
if (hasLet(node.body)) {
node.body = buildNode(node.body);
}
};
exports.BlockStatement = function (node, parent) {
if (!hasLet(node.body)) return;
// ignore if we're the body of a closure already
if (parent.type === "FunctionExpression") return;
node.body = buildNode(node.body);
};
exports.ForOfStatement =
exports.ForInStatement = function (node) {
if (isLet(node.left)) return buildNode(node);
};
exports.ForStatement = function (node) {
if (isLet(node.init)) return buildNode(node);
};
var buildNode = function (node) {
var nodes = [];
// hoist normal variable declarations
node = [].concat(node);
node = node.map(function (node) {
if (node._ignoreBlockBindingHoist) return node;
if (node.type === "VariableDeclaration" && node.kind === "var") {
nodes.push(b.variableDeclaration("var", node.declarations.map(function (declar) {
return b.variableDeclarator(declar.id, null);
})));
return node.declarations.map(function (declar) {
return util.template("assign", {
VALUE: declar.init,
KEY: declar.id
}, true);
});
} else if (node.type === "ForInStatement" && !node.left._ignoreBlockBindingHoist) {
var id = node.left.declarations[0].id;
node.left = id;
nodes.push(util.template("variable-declare", {
KEY: id
}));
}
return node;
});
//
var block = b.blockStatement([]);
block.body = node;
var func = b.functionExpression(null, [], block, false)
var templateName = "function-call";
if (traverse.hasType(node, "ThisExpression")) {
templateName = "function-call-this";
}
//
nodes.push(util.template(templateName, {
FUNCTION: func
}, true));
return nodes;
};