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Reinvent ===
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/** | |
* Reinvent === | |
* @ref [Equality comparisons and sameness](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness) | |
* @ref [JavaScript Equality Table](https://dorey.github.io/JavaScript-Equality-Table/) | |
*/ | |
export const strictEquals = (a, b) => { | |
if (typeof a == 'number' && typeof b == 'number') { | |
if (isNaN(a) && isNaN(b)) { | |
return false; | |
} else if ((Object.is(a, 0) && Object.is(b, -0)) || (Object.is(a, -0) && Object.is(b, 0))) { | |
return true; | |
} | |
} | |
return Object.is(a, b); | |
}; |
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import { strictEquals } from './strictEquals'; | |
const testCases = [ | |
{ values: [undefined, undefined] }, | |
{ values: [null, null] }, | |
{ values: [true] }, | |
{ values: [false] }, | |
{ values: ['foo', 'foo'], keys: ["'foo'", "'foo'"] }, | |
{ values: [0, 0] }, | |
{ values: [+0, -0], keys: ['+0', '-0'] }, | |
{ values: [+0, 0], keys: ['+0'] }, | |
{ values: [-0, 0], keys: ['-0'] }, | |
{ values: [1, 1] }, | |
{ values: [0, 0] }, | |
{ values: [-1, -1] }, | |
{ values: [1, 0] }, | |
{ values: [-1, 0] }, | |
{ values: [-1, 1] }, | |
{ values: [Infinity, Infinity] }, | |
{ values: [-Infinity, -Infinity] }, | |
{ values: [Infinity, -Infinity] }, | |
{ values: [0, false] }, | |
{ values: ['', false], keys: ["''"] }, | |
{ values: ['', 0], keys: ["''"] }, | |
{ values: ['0', 0], keys: ["'0'"] }, | |
{ values: ['17', 17], keys: ["'17'"] }, | |
{ values: [[1, 2], '1,2'], keys: ['[1, 2]', "'1,2'"] }, | |
// eslint-disable-next-line no-new-wrappers | |
{ values: [new String('foo'), 'foo'], keys: ["new String('foo')", "'foo'"] }, | |
{ values: [null, undefined] }, | |
{ values: [null, false] }, | |
{ values: [undefined, false] }, | |
{ values: [{ foo: 'bar' }, { foo: 'bar' }], keys: ["{ foo: 'bar' }", "{ foo: 'bar' }"] }, | |
// eslint-disable-next-line no-new-wrappers | |
{ values: [new String('foo'), new String('foo')], keys: ["new String('foo')", "new String('foo')"] }, | |
{ values: [0, null] }, | |
{ values: [0, NaN] }, | |
{ values: ["'foo'", NaN] }, | |
{ values: [NaN, NaN] }, | |
{ values: [[], []], keys: ['[]', '[]'] }, | |
{ values: [{}, {}], keys: ['{}', '{}'] }, | |
{ values: [[[]], [[]]], keys: ['[[]]', '[[]]'] }, | |
{ values: [[0], [0]], keys: ['[0]', '[0]'] }, | |
{ values: [[1], [1]], keys: ['[1]', '[1]'] }, | |
]; | |
testCases.forEach(({ values, keys }) => { | |
const [ka, kb] = keys && keys.length ? keys : values; | |
const [va, vb] = values; | |
const isStrictEqual = va === vb; | |
test(`${ka || va} === ${kb || vb} -> ${isStrictEqual}`, () => { | |
expect(strictEquals(va, vb)).toBe(isStrictEqual); | |
}); | |
}); |
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