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/* eslint-env mocha */
import assert from 'power-assert'
import differenceInMonths from '.'
describe('differenceInMonths', function () {
it('returns the number of full months between the given dates', function () {
const result = differenceInMonths(
new Date(2012, 6 /* Jul */, 2, 18, 0),
new Date(2011, 6 /* Jul */, 2, 6, 0)
)
assert(result === 12)
})
it('returns a negative number if the time value of the first date is smaller', function () {
const result = differenceInMonths(
new Date(2011, 6 /* Jul */, 2, 6, 0),
new Date(2012, 6 /* Jul */, 2, 18, 0)
)
assert(result === -12)
})
it('accepts timestamps', function () {
const result = differenceInMonths(
new Date(2014, 7 /* Aug */, 2).getTime(),
new Date(2010, 6 /* Jul */, 2).getTime()
)
assert(result === 49)
})
describe('edge cases', function () {
it('it returns diff of 1 month between Feb 28 2021 and Jan 30 2021', function () {
const result = differenceInMonths(
new Date(2021, 1 /* Feb */, 28),
new Date(2021, 0 /* Jan */, 30)
)
assert(result === 1)
})
it('it returns diff of 1 month between Feb 28 2021 and Jan 31 2021', function () {
const result = differenceInMonths(
new Date(2021, 1 /* Feb */, 28),
new Date(2021, 0 /* Jan */, 31)
)
assert(result === 1)
})
it('it returns diff of 1 month between Nov, 30 2021 and Oct, 31 2021', function () {
const result = differenceInMonths(
new Date(2021, 10 /* Nov */, 30),
new Date(2021, 9 /* Oct */, 31)
)
assert(result === 1)
})
it('it returns diff of 1 month between Oct, 31 2021 and Sep, 30 2021', function () {
const result = differenceInMonths(
new Date(2021, 9 /* Oct */, 31),
new Date(2021, 8 /* Sep */, 30)
)
assert(result === 1)
})
it('it returns diff of 6 month between Oct, 31 2021 and Apr, 30 2021', function () {
const result = differenceInMonths(
new Date(2021, 9 /* Oct */, 31),
new Date(2021, 3 /* Apr */, 30)
)
assert(result === 6)
})
it('it returns diff of -1 month between Sep, 30 2021 and Oct, 31 2021', function () {
const result = differenceInMonths(
new Date(2021, 8 /* Sep */, 30),
new Date(2021, 9 /* Oct */, 31)
)
assert(result === -1)
})
it('the difference is less than a month, but the given dates are in different calendar months', function () {
const result = differenceInMonths(
new Date(2014, 7 /* Aug */, 1),
new Date(2014, 6 /* Jul */, 31)
)
assert(result === 0)
})
it('the same for the swapped dates', function () {
const result = differenceInMonths(
new Date(2014, 6 /* Jul */, 31),
new Date(2014, 7 /* Aug */, 1)
)
assert(result === 0)
})
it('the days of months of the given dates are the same', function () {
const result = differenceInMonths(
new Date(2014, 8 /* Sep */, 6),
new Date(2014, 7 /* Aug */, 6)
)
assert(result === 1)
})
it('the given dates are the same', function () {
const result = differenceInMonths(
new Date(2014, 8 /* Sep */, 5, 0, 0),
new Date(2014, 8 /* Sep */, 5, 0, 0)
)
assert(result === 0)
})
it('does not return -0 when the given dates are the same', () => {
function isNegativeZero(x: number): boolean {
return x === 0 && 1 / x < 0
}
const result = differenceInMonths(
new Date(2014, 8 /* Sep */, 5, 0, 0),
new Date(2014, 8 /* Sep */, 5, 0, 0)
)
const resultIsNegative = isNegativeZero(result)
assert(resultIsNegative === false)
})
})
it('returns NaN if the first date is `Invalid Date`', function () {
const result = differenceInMonths(
new Date(NaN),
new Date(2017, 0 /* Jan */, 1)
)
assert(isNaN(result))
})
it('returns NaN if the second date is `Invalid Date`', function () {
const result = differenceInMonths(
new Date(2017, 0 /* Jan */, 1),
new Date(NaN)
)
assert(isNaN(result))
})
it('returns NaN if the both dates are `Invalid Date`', function () {
const result = differenceInMonths(new Date(NaN), new Date(NaN))
assert(isNaN(result))
})
it('throws TypeError exception if passed less than 2 arguments', function () {
assert.throws(differenceInMonths.bind(null), TypeError)
assert.throws(differenceInMonths.bind(null, 1), TypeError)
})
describe('edge cases', function () {
it('returns the number of full months between the given dates - end of Feb', function () {
assert(
differenceInMonths(
new Date(2012, 1 /* Feb */, 29, 9, 0, 0),
new Date(2012, 1 /* Feb */, 29, 10, 0, 0)
) === 0
)
assert(
differenceInMonths(
new Date(2012, 1 /* Feb */, 28, 9, 0, 0),
new Date(2012, 1 /* Feb */, 29, 10, 0, 0)
) === 0
)
assert(
differenceInMonths(
new Date(2012, 1 /* Feb */, 27, 9, 0, 0),
new Date(2012, 1 /* Feb */, 27, 10, 0, 0)
) === 0
)
assert(
differenceInMonths(
new Date(2012, 1 /* Feb */, 28, 9, 0, 0),
new Date(2012, 1 /* Feb */, 28, 10, 0, 0)
) === 0
)
})
assert(
differenceInMonths(
new Date(2021, 1 /* Feb */, 28, 7, 23, 7),
new Date(2021, 1 /* Feb */, 28, 7, 38, 18)
) === 0
)
})
})
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