Sha256: 3331cec237a951b75321e50d6840ba9e5b1861ad1ba5de4ffbc3a218f3e338f5
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Versions: 6
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Stored size: 1.45 KB
Contents
'use strict';
/**
* Cache results of the first function call to ensure only calling once.
*
* ```js
* var lazy = require('lazy-cache')(require);
* // cache the call to `require('ansi-yellow')`
* lazy('ansi-yellow', 'yellow');
* // use `ansi-yellow`
* console.log(lazy.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);
Object.defineProperty(proxy, name, {
get: getter
});
function getter () {
if (cache.hasOwnProperty(name)) {
return cache[name];
}
try {
return (cache[name] = fn(mod));
} catch (err) {
err.message = 'lazy-cache ' + err.message + ' ' + __filename;
throw err;
}
};
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;
Version data entries
6 entries across 6 versions & 2 rubygems