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x/ramda/internal/_indexOf.js

:ram: Practical functional Javascript
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import equals from '../equals';

export default function _indexOf(list, a, idx) { var inf, item; // Array.prototype.indexOf doesn't exist below IE9 if (typeof list.indexOf === 'function') { switch (typeof a) { case 'number': if (a === 0) { // manually crawl the list to distinguish between +0 and -0 inf = 1 / a; while (idx < list.length) { item = list[idx]; if (item === 0 && 1 / item === inf) { return idx; } idx += 1; } return -1; } else if (a !== a) { // NaN while (idx < list.length) { item = list[idx]; if (typeof item === 'number' && item !== item) { return idx; } idx += 1; } return -1; } // non-zero numbers can utilise Set return list.indexOf(a, idx);
// all these types can utilise Set case 'string': case 'boolean': case 'function': case 'undefined': return list.indexOf(a, idx);
case 'object': if (a === null) { // null can utilise Set return list.indexOf(a, idx); } } } // anything else not covered above, defer to R.equals while (idx < list.length) { if (equals(list[idx], a)) { return idx; } idx += 1; } return -1;}