babel/lib/6to5/transformation/helpers/explode-assignable-expression.js
2015-02-10 23:52:23 +11:00

74 lines
1.8 KiB
JavaScript

"use strict";
var t = require("../../types");
var getObjRef = function (node, nodes, file, scope) {
var ref;
if (t.isIdentifier(node)) {
if (scope.hasBinding(node.name)) {
// this variable is declared in scope so we can be 100% sure
// that evaluating it multiple times wont trigger a getter
// or something else
return node;
} else {
// could possibly trigger a getter so we need to only evaluate
// it once
ref = node;
}
} else if (t.isMemberExpression(node)) {
ref = node.object;
if (t.isIdentifier(ref) && scope.hasGlobal(ref.name)) {
// the object reference that we need to save is locally declared
// so as per the previous comment we can be 100% sure evaluating
// it multiple times will be safe
return ref;
}
} else {
throw new Error("We can't explode this node type " + node.type);
}
var temp = scope.generateUidBasedOnNode(ref);
nodes.push(t.variableDeclaration("var", [
t.variableDeclarator(temp, ref)
]));
return temp;
};
var getPropRef = function (node, nodes, file, scope) {
var prop = node.property;
var key = t.toComputedKey(node, prop);
if (t.isLiteral(key)) return key;
var temp = scope.generateUidBasedOnNode(prop);
nodes.push(t.variableDeclaration("var", [
t.variableDeclarator(temp, prop)
]));
return temp;
};
module.exports = function (node, nodes, file, scope, allowedSingleIdent) {
var obj;
if (t.isIdentifier(node) && allowedSingleIdent) {
obj = node;
} else {
obj = getObjRef(node, nodes, file, scope);
}
var ref, uid;
if (t.isIdentifier(node)) {
ref = node;
uid = obj;
} else {
var prop = getPropRef(node, nodes, file, scope);
var computed = node.computed || t.isLiteral(prop);
uid = ref = t.memberExpression(obj, prop, computed);
}
return {
uid: uid,
ref: ref
};
};