Is there a way to achieve the functionality of a <=> b in JavaScript? It seems that this operator does not exist. Any suggestions for an equivalent function?
Appreciate it, Dorian
Is there a way to achieve the functionality of a <=> b in JavaScript? It seems that this operator does not exist. Any suggestions for an equivalent function?
Appreciate it, Dorian
Check out this simple demonstration of the functionality of the "spaceship" operator in JavaScript.
const spaceship = (lhs, rhs) => lhs < rhs ? -1 : rhs < lhs ? 1 : 0;
To incorporate additional type validation, you can leverage the typeof operator to introduce customized comparison logic.
Kindly Note: The localeCompare method will yield either -1, 0, or 1. Comparators within JavaScript function similarly to the <==> operator and are commonly utilized for array sorting operations.
const spaceship = (lhs, rhs) => {
const type = typeof lhs;
if (type !== typeof rhs) { throw new Error('incompatible types') }
if (type === 'string') { return lhs.localeCompare(rhs); }
else if (type === 'number') { return Math.sign(lhs - rhs); }
return lhs < rhs ? -1 : rhs < lhs ? 1 : 0;
}
mocha.setup('bdd')
const { expect } = chai
describe('spaceship operator', () => {
it('integer comparison', () => {
expect(spaceship(1, 1)).to.equal( 0); // 1 <=> 1 === 0
expect(spaceship(1, 2)).to.equal(-1); // 1 <=> 2 === -1
expect(spaceship(2, 1)).to.equal( 1); // 2 <=> 1 === 1
});
it('float comparison', () => {
expect(spaceship(1.5, 1.5)).to.equal( 0); // 1.5 <=> 1.5 === 0
expect(spaceship(1.5, 2.5)).to.equal(-1); // 1.5 <=> 2.5 === -1
expect(spaceship(2.5, 1.5)).to.equal( 1); // 2.5 <=> 1.5 === 1
});
it('string comparison', () => {
expect(spaceship('a', 'a')).to.equal( 0) // 'a' <=> 'a' === 0
expect(spaceship('a', 'b')).to.equal(-1) // 'a' <=> 'b' === -1
expect(spaceship('b', 'a')).to.equal( 1) // 'b' <=> 'a' === 1
});
it('date comparison', () => {
const today = new Date(), yestr = new Date(today.getTime() - 8.64e7);
expect(spaceship(today, today)).to.equal( 0) // 'a' <=> 'a' === 0
expect(spaceship(yestr, today)).to.equal(-1) // 'a' <=> 'b' === -1
expect(spaceship(today, yestr)).to.equal( 1) // 'b' <=> 'a' === 1
});
})
mocha.run()<link href="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.3.4/mocha.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/chai/3.4.1/chai.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mocha/2.3.4/mocha.js"></script>
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