babel/lib/6to5/transformers/destructuring.js
2014-09-29 18:29:08 +10:00

113 lines
2.3 KiB
JavaScript

var util = require("../util");
var _ = require("lodash");
var isPattern = function (id) {
return id.type === "ArrayPattern" || id.type === "ObjectPattern";
};
exports.VariableDeclaration = function (node, parent, opts, generateUid) {
var nodes = [];
var hasPattern = false;
_.each(node.declarations, function (declar) {
if (isPattern(declar.id)) {
hasPattern = true;
return false;
}
});
if (!hasPattern) return;
//
var buildVariableAssign = function (id, init) {
return {
type: "VariableDeclaration",
kind: node.kind,
declarations: [{
type: "VariableDeclarator",
id: id,
init: init
}]
};
};
var push = function (pattern, parentId) {
if (pattern.type === "ObjectPattern") {
pushObjectPattern(pattern, parentId);
} else if (pattern.type === "ArrayPattern") {
pushArrayPattern(pattern, parentId);
}
};
var pushObjectPattern = function (pattern, parentId) {
_.each(pattern.properties, function (prop) {
var id = prop.value;
var init = {
type: "MemberExpression",
object: parentId,
property: prop.key
};
if (isPattern(id)) {
push(id, init);
} else {
nodes.push(buildVariableAssign(id, init));
}
});
};
var pushArrayPattern = function (pattern, parentId) {
_.each(pattern.elements, function (id, i) {
var init = {
type: "MemberExpression",
computed: true,
object: parentId,
property: {
type: "Literal",
value: i
}
};
if (id.type === "Identifier") {
nodes.push(buildVariableAssign(id, init));
} else {
push(id, init);
}
});
};
var pushPattern = function (id, init) {
if (init.type !== "MemberExpression" && init.type !== "Identifier") {
var key = generateUid("ref");
nodes.push(util.template("variable-assign", {
KEY: key,
VALUE: init
}, true));
init = {
type: "Identifier",
name: key
};
}
push(id, init);
};
//
_.each(node.declarations, function (declar) {
var init = declar.init;
var id = declar.id;
if (isPattern(id)) {
pushPattern(id, init);
} else {
nodes.push(buildVariableAssign(id, init));
}
});
return nodes;
};