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import { eqByFn } from './eqBy.js'
test('deteremines whether two values map to the same value in the codomain', () => {  expect(eqByFn(    Math.abs, 5, 5  )).toBe(true)  expect(eqByFn(    Math.abs, 5, -5  )).toBe(true)  expect(eqByFn(    Math.abs, -5, 5  )).toBe(true)  expect(eqByFn(    Math.abs, -5, -5  )).toBe(true)  expect(eqByFn(    Math.abs, 42, 99  )).toBe(false)})
test('has R.equals semantics', () => {  expect(eqByFn(    Math.abs, NaN, NaN  )).toBe(true)  expect(eqByFn(    Math.abs, [ 42 ], [ 42 ]  )).toBe(true)  expect(eqByFn(    x => x, { a : 1 }, { a : 1 }  )).toBe(true)  expect(eqByFn(    x => x, { a : 1 }, { a : 2 }  )).toBe(false)})