Function assertAlmostEquals

assert/almost_equals.ts:33–56

(
  actual: number,
  expected: number,
  tolerance?: number,
  msg?: string,
)

 * @throws {AssertionError} If the values are not almost equal.
 */
export function assertAlmostEquals(
  actual: number,
  expected: number,
  tolerance?: number,
  msg?: string,
) {
  if (Object.is(actual, expected)) {
    return;
  }
  const delta = Math.abs(expected - actual);
  if (tolerance === undefined) {
    tolerance = isFinite(expected) ? Math.abs(expected * 1e-7) : 1e-7;
  }
  if (delta <= tolerance) {
    return;
  }

  const msgSuffix = msg ? `: ${msg}` : ".";
  const f = (n: number) => Number.isInteger(n) ? n : n.toExponential();
  throw new AssertionError(
    `Expected actual: "${f(actual)}" to be close to "${f(expected)}": \
delta "${f(delta)}" is greater than "${f(tolerance)}"${msgSuffix}`,
  );
}