Method constructor

lib/internal/assert/assertion_error.js:250–386

(options)

class AssertionError extends Error {
  constructor(options) {
    validateObject(options, 'options');
    const {
      message,
      operator,
      stackStartFn,
      details,
      // Compatibility with older versions.
      stackStartFunction,
      diff = 'simple',
    } = options;
    let {
      actual,
      expected,
    } = options;

    const limit = Error.stackTraceLimit;
    if (isErrorStackTraceLimitWritable()) Error.stackTraceLimit = 0;

    if (message != null) {
      if (kMethodsWithCustomMessageDiff.has(operator)) {
        super(createErrDiff(actual, expected, operator, message, diff));
      } else {
        super(String(message));
      }
    } else {
      // Reset colors on each call to make sure we handle dynamically set environment
      // variables correct.
      colors.refresh();
      // Prevent the error stack from being visible by duplicating the error
      // in a very close way to the original in case both sides are actually
      // instances of Error.
      if (typeof actual === 'object' && actual !== null &&
          typeof expected === 'object' && expected !== null &&
          'stack' in actual && actual instanceof Error &&
          'stack' in expected && expected instanceof Error) {
        actual = copyError(actual);
        expected = copyError(expected);
      }

      if (kMethodsWithCustomMessageDiff.has(operator)) {
        super(createErrDiff(actual, expected, operator, message, diff));
      } else if (operator === 'notDeepStrictEqual' ||
        operator === 'notStrictEqual') {
        // In case the objects are equal but the operator requires unequal, show
        // the first object and say A equals B
        let base = kReadableOperator[operator];
        const res = StringPrototypeSplit(inspectValue(actual), '\n');

        // In case "actual" is an object or a function, it should not be
        // reference equal.
        if (operator === 'notStrictEqual' &&
            ((typeof actual === 'object' && actual !== null) ||
             typeof actual === 'function')) {
          base = kReadableOperator.notStrictEqualObject;
        }

        // Only remove lines in case it makes sense to collapse those.