62 lines
1.5 KiB
JavaScript
62 lines
1.5 KiB
JavaScript
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'use strict';
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var GetIntrinsic = require('get-intrinsic');
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var $Number = GetIntrinsic('%Number%');
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var $TypeError = GetIntrinsic('%TypeError%');
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var $isNaN = require('../helpers/isNaN');
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var $isFinite = require('../helpers/isFinite');
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var IsStringPrefix = require('./IsStringPrefix');
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var ToNumber = require('./ToNumber');
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var ToPrimitive = require('./ToPrimitive');
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var Type = require('./Type');
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// https://262.ecma-international.org/9.0/#sec-abstract-relational-comparison
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module.exports = function AbstractRelationalComparison(x, y, LeftFirst) {
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if (Type(LeftFirst) !== 'Boolean') {
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throw new $TypeError('Assertion failed: LeftFirst argument must be a Boolean');
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}
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var px;
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var py;
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if (LeftFirst) {
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px = ToPrimitive(x, $Number);
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py = ToPrimitive(y, $Number);
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} else {
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py = ToPrimitive(y, $Number);
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px = ToPrimitive(x, $Number);
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}
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if (Type(px) === 'String' && Type(py) === 'String') {
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if (IsStringPrefix(py, px)) {
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return false;
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}
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if (IsStringPrefix(px, py)) {
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return true;
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}
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return px < py; // both strings, neither a prefix of the other. shortcut for steps 3 c-f
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}
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var nx = ToNumber(px);
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var ny = ToNumber(py);
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if ($isNaN(nx) || $isNaN(ny)) {
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return undefined;
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}
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if ($isFinite(nx) && $isFinite(ny) && nx === ny) {
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return false;
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}
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if (nx === Infinity) {
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return false;
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}
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if (ny === Infinity) {
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return true;
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}
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if (ny === -Infinity) {
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return false;
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}
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if (nx === -Infinity) {
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return true;
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}
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return nx < ny; // by now, these are both nonzero, finite, and not equal
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};
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