feat: support filter expression with value null (#5) #7

	name: CI

	on:
	push:
	branches:
	- master
	jobs:
	build:
	runs-on: ubuntu-latest

	steps:
	- name: Checkout code
	uses: actions/checkout@v2

	- name: Setup Node.js
	uses: actions/setup-node@v2
	with:
	node-version: '12'

	- name: Restore cache
	uses: actions/cache@v2
	with:
	path: ~/.npm
	key: dependency-cache-${{ hashFiles('package-lock.json') }}
	restore-keys: \|
	dependency-cache-${{ hashFiles('package-lock.json') }}

	- name: Install dependencies
	run: npm ci

	- name: Run tests
	run: npm run test

	- name: Store coverage artifacts
	uses: actions/upload-artifact@v2
	with:
	name: coverage
	path: coverage/

	- name: Upload coverage to Codecov
	uses: codecov/codecov-action@v1
	with:
	file: ./coverage/coverage-final.json

Provide feedback