Function createPredicateFn

test/angular/1.5/angular.js:20531–20566

(expression, comparator, anyPropertyKey, matchAgainstAnyProp)

// Helper functions for `filterFilter`
function createPredicateFn(expression, comparator, anyPropertyKey, matchAgainstAnyProp) {
  var shouldMatchPrimitives = isObject(expression) && (anyPropertyKey in expression);
  var predicateFn;

  if (comparator === true) {
    comparator = equals;
  } else if (!isFunction(comparator)) {
    comparator = function(actual, expected) {
      if (isUndefined(actual)) {
        // No substring matching against `undefined`
        return false;
      }
      if ((actual === null) || (expected === null)) {
        // No substring matching against `null`; only match against `null`
        return actual === expected;
      }
      if (isObject(expected) || (isObject(actual) && !hasCustomToString(actual))) {
        // Should not compare primitives against objects, unless they have custom `toString` method
        return false;
      }

      actual = lowercase('' + actual);
      expected = lowercase('' + expected);
      return actual.indexOf(expected) !== -1;
    };
  }

  predicateFn = function(item) {
    if (shouldMatchPrimitives && !isObject(item)) {
      return deepCompare(item, expression[anyPropertyKey], comparator, anyPropertyKey, false);
    }
    return deepCompare(item, expression, comparator, anyPropertyKey, matchAgainstAnyProp);
  };

  return predicateFn;
}

function deepCompare(actual, expected, comparator, anyPropertyKey, matchAgainstAnyProp, dontMatchWholeObject) {
  var actualType = getTypeForFilter(actual);