util_test.js

import { asyncThrottle, hash } from '../src/util.js'
import { generateSimpleViteManifest, wait } from './util.js'
import { expect } from 'chai'
import sinon from 'sinon'

const sandbox = sinon.createSandbox()

describe('Util', function () {
  describe('hash function', function () {
    it('computes the hash', function () {
      const manifest = generateSimpleViteManifest({
        'example.js': { imports: ['test.css'] },
        'test.css': { }
      })
      expect(hash(manifest)).to.equal('2245696177')
    })

    it('the hash changes when the manifest changes', function () {
      const manifest = generateSimpleViteManifest({
        'example.js': { imports: ['test.css'] },
        'test.css': { }
      })
      const manifestChanged = generateSimpleViteManifest({
        'example.js': { imports: ['test1.css'] },
        'test1.css': { }
      })

      expect(hash(manifest)).not.to.equal(hash(manifestChanged))
      expect(hash(manifest)).to.equal('2245696177')
      expect(hash(manifestChanged)).to.equal('2547998666')
    })
  })

  describe('asyncThrottle function', function () {
    let spy
    beforeEach(function () {
      spy = sandbox.spy(function () {
        return new Promise((resolve, reject) => {
          // @ts-ignore
          spy.resolve = resolve
          // @ts-ignore
          spy.reject = resolve
        })
      })
    })

    it('works', function () {
      const throttled = asyncThrottle(spy)
      expect(spy.callCount).to.equal(0)
      throttled()
      expect(spy.callCount).to.equal(1)
    })

    it('is only called once again on the trailing edge', async function () {
      const throttled = asyncThrottle(spy)
      expect(spy.callCount).to.equal(0)
      throttled()
      expect(spy.callCount).to.equal(1)
      throttled()
      expect(spy.callCount).to.equal(1)
      spy.resolve()
      await wait(0)
      expect(spy.callCount).to.equal(2)
      spy.resolve()
      await wait(0)
      expect(spy.callCount).to.equal(2)
    })
  })
})