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import {mergeLeft} from './mergeLeft'
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)})