babel/lib/6to5/transformation/helpers/build-conditional-assignment-operator-transformer.js
2015-01-17 22:56:49 +11:00

76 lines
1.9 KiB
JavaScript

var t = require("../../types");
module.exports = function (opts) {
var getObjRef = function (node, nodes, file, scope) {
var obj = node.object;
var temp = scope.generateUidBasedOnNode(obj, file);
nodes.push(t.variableDeclaration("var", [
t.variableDeclarator(temp, obj)
]));
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, file);
nodes.push(t.variableDeclaration("var", [
t.variableDeclarator(temp, prop)
]));
return temp;
};
var buildAbsoluteRef = function (node, nodes, file, scope) {
if (t.isIdentifier(node)) return node;
var obj = getObjRef(node, nodes, file, scope);
var prop = getPropRef(node, nodes, file, scope);
var computed = node.computed || t.isLiteral(prop);
return t.memberExpression(obj, prop, computed);
};
var buildAssignment = function (left, right) {
return t.assignmentExpression("=", left, right);
};
var exports = {};
exports.ExpressionStatement = function (node, parent, scope, context, file) {
var expr = node.expression;
if (!opts.is(expr)) return;
var nodes = [];
var left = buildAbsoluteRef(expr.left, nodes, file, scope);
nodes.push(t.ifStatement(
opts.build(left, file),
t.expressionStatement(buildAssignment(left, expr.right))
));
return nodes;
};
exports.AssignmentExpression = function (node, parent, scope, context, file) {
if (t.isExpressionStatement(parent)) return;
if (!opts.is(node)) return;
var nodes = [];
var left = buildAbsoluteRef(node.left, nodes, file, scope);
nodes.push(t.logicalExpression(
"&&",
opts.build(left, file),
buildAssignment(left, node.right)
));
nodes.push(left);
return t.toSequenceExpression(nodes, scope);
};
return exports;
};