44 lines
1.2 KiB
JavaScript
44 lines
1.2 KiB
JavaScript
/**
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* Composes single-argument functions from right to left. The rightmost
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* function can take multiple arguments as it provides the signature for
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* the resulting composite function.
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*
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* @param {...Function} funcs The functions to compose.
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* @returns {Function} A function obtained by composing the argument functions
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* from right to left. For example, compose(f, g, h) is identical to doing
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* (...args) => f(g(h(...args))).
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*/
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export function compose(...funcs) {
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if (funcs.length === 0) {
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return arg => arg;
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}
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if (funcs.length === 1) {
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return funcs[0];
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}
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return funcs.reduce((a, b) => (...args) => a(b(...args)));
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}
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export function fastApply(holder, fn, args) {
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if (holder || args.length > 5) {
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return fn.apply(holder, args);
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}
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if (0 === args.length) {
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return fn();
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}
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if (1 === args.length) {
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return fn(args[0]);
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}
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if (2 === args.length) {
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return fn(args[0], args[1]);
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}
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if (3 === args.length) {
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return fn(args[0], args[1], args[2]);
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}
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if (4 === args.length) {
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return fn(args[0], args[1], args[2], args[3]);
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}
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if (5 === args.length) {
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return fn(args[0], args[1], args[2], args[3], args[4]);
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}
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}
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