/**
* Copyright 2017 Google 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.
*/
/**
* @fileoverview Contains helper methods for manipulating paths.
*/
/**
* @return Null if the path is already at the root.
*/
export function parent(path: string): string | null {
if (path.length == 0) {
return null;
}
let index = path.lastIndexOf('/');
if (index === -1) {
return '';
}
let newPath = path.slice(0, index);
return newPath;
}
export function child(path: string, childPath: string): string {
let canonicalChildPath = childPath
.split('/')
.filter(function(component) {
return component.length > 0;
})
.join('/');
if (path.length === 0) {
return canonicalChildPath;
} else {
return path + '/' + canonicalChildPath;
}
}
/**
* Returns the last component of a path.
* '/foo/bar' -> 'bar'
* '/foo/bar/baz/' -> 'baz/'
* '/a' -> 'a'
*/
export function lastComponent(path: string): string {
let index = path.lastIndexOf('/', path.length - 2);
if (index === -1) {
return path;
} else {
return path.slice(index + 1);
}
}
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