/
jest-extend.ts
130 lines (109 loc) · 3.76 KB
/
jest-extend.ts
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import { util } from 'chai'
import type {
ChaiPlugin,
ExpectStatic,
MatcherState,
MatchersObject,
SyncExpectationResult,
} from './types'
import { JEST_MATCHERS_OBJECT } from './constants'
import { AsymmetricMatcher } from './jest-asymmetric-matchers'
import { getState } from './state'
import { diff, getMatcherUtils, stringify } from './jest-matcher-utils'
import {
equals,
iterableEquality,
subsetEquality,
} from './jest-utils'
function getMatcherState(assertion: Chai.AssertionStatic & Chai.Assertion, expect: ExpectStatic) {
const obj = assertion._obj
const isNot = util.flag(assertion, 'negate') as boolean
const promise = util.flag(assertion, 'promise') || ''
const jestUtils = {
...getMatcherUtils(),
diff,
stringify,
iterableEquality,
subsetEquality,
}
const matcherState: MatcherState = {
...getState(expect),
isNot,
utils: jestUtils,
promise,
equals,
// needed for built-in jest-snapshots, but we don't use it
suppressedErrors: [],
}
return {
state: matcherState,
isNot,
obj,
}
}
class JestExtendError extends Error {
constructor(message: string, public actual?: any, public expected?: any) {
super(message)
}
}
function JestExtendPlugin(expect: ExpectStatic, matchers: MatchersObject): ChaiPlugin {
return (c, utils) => {
Object.entries(matchers).forEach(([expectAssertionName, expectAssertion]) => {
function expectWrapper(this: Chai.AssertionStatic & Chai.Assertion, ...args: any[]) {
const { state, isNot, obj } = getMatcherState(this, expect)
// @ts-expect-error args wanting tuple
const result = expectAssertion.call(state, obj, ...args)
if (result && typeof result === 'object' && result instanceof Promise) {
return result.then(({ pass, message, actual, expected }) => {
if ((pass && isNot) || (!pass && !isNot))
throw new JestExtendError(message(), actual, expected)
})
}
const { pass, message, actual, expected } = result
if ((pass && isNot) || (!pass && !isNot))
throw new JestExtendError(message(), actual, expected)
}
utils.addMethod((globalThis as any)[JEST_MATCHERS_OBJECT].matchers, expectAssertionName, expectWrapper)
utils.addMethod(c.Assertion.prototype, expectAssertionName, expectWrapper)
class CustomMatcher extends AsymmetricMatcher<[unknown, ...unknown[]]> {
constructor(inverse = false, ...sample: [unknown, ...unknown[]]) {
super(sample, inverse)
}
asymmetricMatch(other: unknown) {
const { pass } = expectAssertion.call(
this.getMatcherContext(expect),
other,
...this.sample,
) as SyncExpectationResult
return this.inverse ? !pass : pass
}
toString() {
return `${this.inverse ? 'not.' : ''}${expectAssertionName}`
}
getExpectedType() {
return 'any'
}
toAsymmetricMatcher() {
return `${this.toString()}<${this.sample.map(String).join(', ')}>`
}
}
Object.defineProperty(expect, expectAssertionName, {
configurable: true,
enumerable: true,
value: (...sample: [unknown, ...unknown[]]) => new CustomMatcher(false, ...sample),
writable: true,
})
Object.defineProperty(expect.not, expectAssertionName, {
configurable: true,
enumerable: true,
value: (...sample: [unknown, ...unknown[]]) => new CustomMatcher(true, ...sample),
writable: true,
})
})
}
}
export const JestExtend: ChaiPlugin = (chai, utils) => {
utils.addMethod(chai.expect, 'extend', (expect: ExpectStatic, expects: MatchersObject) => {
chai.use(JestExtendPlugin(expect, expects))
})
}