Mario Romano 29df96a085 react app
2016-04-06 17:52:19 +01:00

107 lines
3.1 KiB
JavaScript

/**
* Copyright 2013 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*jslint node:true*/
/**
* Desugars ES6 rest parameters into an ES3 arguments array.
*
* function printf(template, ...args) {
* args.forEach(...);
* }
*
* We could use `Array.prototype.slice.call`, but that usage of arguments causes
* functions to be deoptimized in V8, so instead we use a for-loop.
*
* function printf(template) {
* for (var args = [], $__0 = 1, $__1 = arguments.length; $__0 < $__1; $__0++)
* args.push(arguments[$__0]);
* args.forEach(...);
* }
*
*/
var Syntax = require('esprima-fb').Syntax;
var utils = require('../src/utils');
function _nodeIsFunctionWithRestParam(node) {
return (node.type === Syntax.FunctionDeclaration
|| node.type === Syntax.FunctionExpression
|| node.type === Syntax.ArrowFunctionExpression)
&& node.rest;
}
function visitFunctionParamsWithRestParam(traverse, node, path, state) {
if (node.parametricType) {
utils.catchup(node.parametricType.range[0], state);
path.unshift(node);
traverse(node.parametricType, path, state);
path.shift();
}
// Render params.
if (node.params.length) {
path.unshift(node);
traverse(node.params, path, state);
path.shift();
} else {
// -3 is for ... of the rest.
utils.catchup(node.rest.range[0] - 3, state);
}
utils.catchupWhiteSpace(node.rest.range[1], state);
path.unshift(node);
traverse(node.body, path, state);
path.shift();
return false;
}
visitFunctionParamsWithRestParam.test = function(node, path, state) {
return _nodeIsFunctionWithRestParam(node);
};
function renderRestParamSetup(functionNode, state) {
var idx = state.localScope.tempVarIndex++;
var len = state.localScope.tempVarIndex++;
return 'for (var ' + functionNode.rest.name + '=[],' +
utils.getTempVar(idx) + '=' + functionNode.params.length + ',' +
utils.getTempVar(len) + '=arguments.length;' +
utils.getTempVar(idx) + '<' + utils.getTempVar(len) + ';' +
utils.getTempVar(idx) + '++) ' +
functionNode.rest.name + '.push(arguments[' + utils.getTempVar(idx) + ']);';
}
function visitFunctionBodyWithRestParam(traverse, node, path, state) {
utils.catchup(node.range[0] + 1, state);
var parentNode = path[0];
utils.append(renderRestParamSetup(parentNode, state), state);
return true;
}
visitFunctionBodyWithRestParam.test = function(node, path, state) {
return node.type === Syntax.BlockStatement
&& _nodeIsFunctionWithRestParam(path[0]);
};
exports.renderRestParamSetup = renderRestParamSetup;
exports.visitorList = [
visitFunctionParamsWithRestParam,
visitFunctionBodyWithRestParam
];