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stared/jest_typescript_extend.ts

Created February 13, 2020 23:17
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  1. stared created this gist Feb 13, 2020.
    21 changes: 21 additions & 0 deletions jest_typescript_extend.ts
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,21 @@
    export {}

    declare global {
    namespace jest {
    interface Matchers<R> {
    myMatcher: (received: string) => R
    }
    }
    }

    function myMatcher<T>(this: jest.MatcherUtils, received: string, expected: string): jest.CustomMatcherResult {
    const pass = received === expected
    return {
    pass,
    message: (): string => `expected ${received} to be ${expected}`,
    }
    }

    expect.extend({
    myMatcher,
    })