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var debounce = require('.')var sinon = require('sinon')
describe('housekeeping', function() { it('should be defined as a function', function() { expect(typeof debounce).toEqual('function') })})
describe('catch issue #3 - Debounced function executing early?', function() {
// use sinon to control the clock
var clock
beforeEach(function(){ clock = sinon.useFakeTimers() })
afterEach(function(){ clock.restore() })
it('should debounce with fast timeout', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
// call debounced function at interval of 50
setTimeout(fn, 100) setTimeout(fn, 150) setTimeout(fn, 200) setTimeout(fn, 250)
// set the clock to 100 (period of the wait) ticks after the last debounced call
clock.tick(350)
// the callback should have been triggered once
expect(callback.callCount).toEqual(1)
})
})
describe('forcing execution', function() {
// use sinon to control the clock
var clock
beforeEach(function(){ clock = sinon.useFakeTimers() })
afterEach(function(){ clock.restore() })
it('should not execute prior to timeout', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
// call debounced function at interval of 50
setTimeout(fn, 100) setTimeout(fn, 150)
// set the clock to 25 (period of the wait) ticks after the last debounced call
clock.tick(175)
// the callback should not have been called yet
expect(callback.callCount).toEqual(0)
})
it('should execute prior to timeout when flushed', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
// call debounced function at interval of 50
setTimeout(fn, 100) setTimeout(fn, 150)
// set the clock to 25 (period of the wait) ticks after the last debounced call
clock.tick(175) fn.flush()
// the callback has been called
expect(callback.callCount).toEqual(1)
})
it('should not execute again after timeout when flushed before the timeout', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
// call debounced function at interval of 50
setTimeout(fn, 100) setTimeout(fn, 150)
// set the clock to 25 (period of the wait) ticks after the last debounced call
clock.tick(175) fn.flush() // the callback has been called here
expect(callback.callCount).toEqual(1) // move to past the timeout
clock.tick(225)
// the callback should have only been called once
expect(callback.callCount).toEqual(1)
})
it('should not execute on a timer after being flushed', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
// call debounced function at interval of 50
setTimeout(fn, 100) setTimeout(fn, 150)
// set the clock to 25 (period of the wait) ticks after the last debounced call
clock.tick(175) fn.flush() // the callback has been called here
expect(callback.callCount).toEqual(1) // schedule again
setTimeout(fn, 250) // move to past the new timeout
clock.tick(400)
// the callback should have been called again
expect(callback.callCount).toEqual(2)
})
it('should not execute when flushed if nothing was scheduled', function() {
var callback = sinon.spy()
// set up debounced function with wait of 100
var fn = debounce(callback, 100)
fn.flush() // the callback should not have been called
expect(callback.callCount).toEqual(0)
})
})
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