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author | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
commit | de98e0b232509d5f40c135d540a70e415272ff85 (patch) | |
tree | a79222a5b58484ab3b80d18efcaaa7ccc4769b33 /node_modules/lazy-cache/index.js | |
parent | e0c9d480a73fa629c1e4a47d3e721f1d2d345406 (diff) | |
download | wallet-core-de98e0b232509d5f40c135d540a70e415272ff85.tar.xz |
node_modules
Diffstat (limited to 'node_modules/lazy-cache/index.js')
-rw-r--r-- | node_modules/lazy-cache/index.js | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/node_modules/lazy-cache/index.js b/node_modules/lazy-cache/index.js new file mode 100644 index 000000000..da7897d0c --- /dev/null +++ b/node_modules/lazy-cache/index.js @@ -0,0 +1,67 @@ +'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; |