58 lines
2.0 KiB
JavaScript
58 lines
2.0 KiB
JavaScript
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import _arity from "./internal/_arity.js";
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import _curry2 from "./internal/_curry2.js";
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import _has from "./internal/_has.js";
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/**
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* Takes a string-returning function `keyGen` and a function `fn` and returns
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* a new function that returns cached results for subsequent
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* calls with the same arguments.
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*
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* When the function is invoked, `keyGen` is applied to the same arguments
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* and its result becomes the cache key. If the cache contains something
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* under that key, the function simply returns it and does not invoke `fn` at all.
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*
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* Otherwise `fn` is applied to the same arguments and its return value
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* is cached under that key and returned by the function.
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*
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* Care must be taken when implementing `keyGen` to avoid key collision,
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* or if tracking references, memory leaks and mutating arguments.
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*
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* @func
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* @memberOf R
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* @since v0.24.0
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* @category Function
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* @sig (*... -> String) -> (*... -> a) -> (*... -> a)
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* @param {Function} keyGen The function to generate the cache key.
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* @param {Function} fn The function to memoize.
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* @return {Function} Memoized version of `fn`.
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* @example
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* const withAge = memoizeWith(o => `${o.birth}/${o.death}`, ({birth, death}) => {
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* // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^
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* // keyGen fn
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* console.log(`computing age for ${birth}/${death}`);
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* return ({birth, death, age: death - birth});
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* });
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*
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* withAge({birth: 1921, death: 1999});
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* //=> LOG: computing age for 1921/1999
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* //=> {birth: 1921, death: 1999, age: 78} (returned from fn)
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*
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* withAge({birth: 1921, death: 1999});
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* //=> {birth: 1921, death: 1999, age: 78} (returned from cache)
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*/
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var memoizeWith =
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/*#__PURE__*/
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_curry2(function memoizeWith(keyGen, fn) {
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var cache = {};
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return _arity(fn.length, function () {
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var key = keyGen.apply(this, arguments);
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if (!_has(key, cache)) {
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cache[key] = fn.apply(this, arguments);
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}
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return cache[key];
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});
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});
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export default memoizeWith;
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