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- 'use strict';
- /**
- * Cache results of the first function call to ensure only calling once.
- *
- * ```js
- * var utils = require('lazy-cache')(require);
- * // cache the call to `require('ansi-yellow')`
- * utils('ansi-yellow', 'yellow');
- * // use `ansi-yellow`
- * console.log(utils.yellow('this is yellow'));
- * ```
- *
- * @param {Function} `fn` Function that will be called only once.
- * @return {Function} Function that can be called to get the cached function
- * @api public
- */
- function lazyCache(fn) {
- var cache = {};
- var proxy = function(mod, name) {
- name = name || camelcase(mod);
- // check both boolean and string in case `process.env` cases to string
- if (process.env.UNLAZY === 'true' || process.env.UNLAZY === true || process.env.TRAVIS) {
- cache[name] = fn(mod);
- }
- Object.defineProperty(proxy, name, {
- enumerable: true,
- configurable: true,
- get: getter
- });
- function getter() {
- if (cache.hasOwnProperty(name)) {
- return cache[name];
- }
- return (cache[name] = fn(mod));
- }
- return getter;
- };
- return proxy;
- }
- /**
- * Used to camelcase the name to be stored on the `lazy` object.
- *
- * @param {String} `str` String containing `_`, `.`, `-` or whitespace that will be camelcased.
- * @return {String} camelcased string.
- */
- function camelcase(str) {
- if (str.length === 1) {
- return str.toLowerCase();
- }
- str = str.replace(/^[\W_]+|[\W_]+$/g, '').toLowerCase();
- return str.replace(/[\W_]+(\w|$)/g, function(_, ch) {
- return ch.toUpperCase();
- });
- }
- /**
- * Expose `lazyCache`
- */
- module.exports = lazyCache;
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