react/scripts/babel/transform-object-assign-req...

43 lines
1.0 KiB
JavaScript

/**
* Copyright (c) 2013-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
'use strict';
module.exports = function autoImporter(babel) {
function getAssignIdent(path, file, state) {
if (state.id) {
return state.id;
}
state.id = file.addImport('object-assign', 'default', 'assign');
return state.id;
}
return {
pre: function() {
// map from module to generated identifier
this.id = null;
},
visitor: {
CallExpression: function(path, file) {
if (path.get('callee').matchesPattern('Object.assign')) {
// generate identifier and require if it hasn't been already
const id = getAssignIdent(path, file, this);
path.node.callee = id;
}
},
MemberExpression: function(path, file) {
if (path.matchesPattern('Object.assign')) {
const id = getAssignIdent(path, file, this);
path.replaceWith(id);
}
},
},
};
};