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import { mergeLeft } from './mergeLeft.js'
const obj = {  foo : 1,  bar : 2,}
test('happy', () => {  expect(mergeLeft({ bar : 20 }, obj)).toEqual({    foo : 1,    bar : 20,  })})
test('curry', () => {  expect(mergeLeft({ baz : 3 })(obj)).toEqual({    foo : 1,    bar : 2,    baz : 3,  })})
test('when undefined or null instead of object', () => {  expect(mergeLeft(null, undefined)).toEqual({})  expect(mergeLeft(obj, null)).toEqual(obj)  expect(mergeLeft(obj, undefined)).toEqual(obj)  expect(mergeLeft(undefined, obj)).toEqual(obj)})