Function toBeCloseTo

packages/expect/src/matchers.ts:142–213

(received: number, expected: number, precision = 2)

  },

  toBeCloseTo(received: number, expected: number, precision = 2) {
    const matcherName = 'toBeCloseTo';
    const secondArgument = arguments.length === 3 ? 'precision' : undefined;
    const isNot = this.isNot;
    const options: MatcherHintOptions = {
      isNot,
      promise: this.promise,
      secondArgument,
      secondArgumentColor: (arg: string) => arg,
    };

    if (typeof expected !== 'number') {
      throw new TypeError(
        matcherErrorMessage(
          matcherHint(matcherName, undefined, undefined, options),
          `${EXPECTED_COLOR('expected')} value must be a number`,
          printWithType('Expected', expected, printExpected),
        ),
      );
    }

    if (typeof received !== 'number') {
      throw new TypeError(
        matcherErrorMessage(
          matcherHint(matcherName, undefined, undefined, options),
          `${RECEIVED_COLOR('received')} value must be a number`,
          printWithType('Received', received, printReceived),
        ),
      );
    }

    let pass = false;
    let expectedDiff = 0;
    let receivedDiff = 0;

    if (
      received === Number.POSITIVE_INFINITY &&
      expected === Number.POSITIVE_INFINITY
    ) {
      pass = true; // Infinity - Infinity is NaN
    } else if (
      received === Number.NEGATIVE_INFINITY &&
      expected === Number.NEGATIVE_INFINITY
    ) {
      pass = true; // -Infinity - -Infinity is NaN
    } else {
      expectedDiff = Math.pow(10, -precision) / 2;
      receivedDiff = Math.abs(expected - received);
      pass = receivedDiff < expectedDiff;
    }

    const message = pass
      ? () =>
          // eslint-disable-next-line prefer-template
          matcherHint(matcherName, undefined, undefined, options) +
          '\n\n' +
          `Expected: not ${printExpected(expected)}\n` +
          (receivedDiff === 0