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Version: 4.x

List of Enforce rules

Enforce rules are functions that allow you to test your data against different criteria. The following rules are supported out-of-the-box.

equals​

Description​

Checks if your enforced value strictly equals (===) another.

It is not recommended to use this rule to compare arrays or objects, as it does not perform any sort of deep comparison on the value.

For numeric value comparison, you should use numberEquals, which coerces numeric strings into numbers before comparing.

Arguments​

  • value: Any value you wish to check your enforced value against

Usage examples:​

enforce(1).equals(1);

enforce('hello').equals('hello');

const a = [1, 2, 3];

enforce(a).equals(a);
// passes
enforce('1').equals(1);
enforce([1, 2, 3]).equals([1, 2, 3]);
// throws

notEquals​

Description​

Checks if your enforced value does not strictly equal (===) another.

Reverse implementation of equals.

Usage examples:​

enforce('1').notEquals(1);
enforce([1, 2, 3]).notEquals([1, 2, 3]);
// passes
enforce(1).notEquals(1);
enforce('hello').notEquals('hello');

const a = [1, 2, 3];

enforce(a).notEquals(a);
// throws

isEmpty​

Description​

Checks if your enforced value is empty, false, zero, null or undefined.

Expected results are:

  • object: checks against the count of keys (0 is empty)
  • array/string: checks against length. (0 is empty)
  • number: checks the value of the number. (0 and NaN are empty)
  • boolean: false is empty.
  • undefined/null: are both empty.

Usage examples:​

enforce([]).isEmpty();
enforce('').isEmpty();
enforce({}).isEmpty();
enforce(0).isEmpty();
enforce(NaN).isEmpty();
enforce(undefined).isEmpty();
enforce(null).isEmpty();
enforce(false).isEmpty();
// passes
enforce([1]).isEmpty();
enforce('1').isEmpty();
enforce({ 1: 1 }).isEmpty();
enforce(1).isEmpty();
enforce(true).isEmpty();
// throws

isNotEmpty​

Description​

Checks that your enforced value is not empty, false, or zero. Reverse implementation of isEmpty.

Usage examples:​

enforce([1]).isNotEmpty();
enforce('1').isNotEmpty();
enforce({ 1: 1 }).isNotEmpty();
// passes
enforce([]).isNotEmpty();
enforce('').isNotEmpty();
enforce({}).isNotEmpty();
enforce(0).isNotEmpty();
// throws

isNumeric​

Description​

Checks if a value is a representation of a real number

Usage examples:​

enforce(143).isNumeric();
enforce('143').isNumeric();
// passes
enforce(NaN).isNumeric();
enforce('1hello').isNumeric();
enforce('hi').isNumeric();
// throws

isNotNumeric​

Description​

Checks if a value is not a representation of a real number. Reverse implementation of isNumeric.

Usage examples:​

enforce(NaN).isNotNumeric();
enforce('Hello World!').isNotNumeric();
// passes
enforce(731).isNotNumeric();
enforce('42').isNotNumeric();
// throws

greaterThan​

  • alias: gt

Description​

Checks that your numeric enforced value is larger than a given numeric value.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(1).greaterThan(0);
enforce('10').greaterThan(0);
enforce(900).gt('100');
// passes
enforce(100).greaterThan(100);
enforce('100').greaterThan(110);
enforce([100]).gt(1);
// throws

greaterThanOrEquals​

  • alias: gte()

Description​

Checks that your numeric enforced value is larger than or equals a given numeric value.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(1).greaterThanOrEquals(0);
enforce('10').greaterThanOrEquals(0);
enforce(900).greaterThanOrEquals('100');
enforce(100).greaterThanOrEquals('100');
enforce(900).gte('900');
enforce('1337').gte(1337);
// passes
enforce(100).greaterThanOrEquals('120');
enforce('100').greaterThanOrEquals(110);
enforce([100]).gte(1);
// throws

lengthEquals​

Description​

Checks that your enforced value is equal to the given number.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([1]).lengthEquals(1);
enforce('a').lengthEquals(1);
// passes
enforce([1, 2]).lengthEquals(1);
enforce('').lengthEquals(1);
// throws

lengthNotEquals​

Description​

Checks that your enforced value is not equal to the given number. Reverse implementation of lengthEquals.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([1]).lengthNotEquals(0);
enforce('a').lengthNotEquals(3);
// passes
enforce([1]).lengthNotEquals(1);
enforce('').lengthNotEquals(0);
// throws

lessThan​

  • alias: lt()

Description​

Checks that your numeric enforced value is smaller than a given numeric value.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(0).lessThan(1);
enforce(2).lessThan('10');
enforce('90').lt(100);
// passes
enforce(100).lessThan(100);
enforce('110').lessThan(100);
enforce([0]).lt(1);
// throws

lessThanOrEquals​

  • alias: lte()

Description​

Checks that your numeric enforced value is smaller than or equals a given numeric value.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(0).lessThanOrEquals(1);
enforce(2).lessThanOrEquals('10');
enforce('90').lte(100);
enforce(100).lte('100');
// passes
enforce(100).lessThanOrEquals(90);
enforce('110').lessThanOrEquals(100);
enforce([0]).lte(1);
// throws

longerThan​

Description​

Checks that your enforced value is longer than a given number.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([1]).longerThan(0);
enforce('ab').longerThan(1);
// passes
enforce([1]).longerThan(2);
enforce('').longerThan(0);
// throws

longerThanOrEquals​

Description​

Checks that your enforced value is longer than or equals a given number.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([1]).longerThanOrEquals(0);
enforce('ab').longerThanOrEquals(1);
enforce([1]).longerThanOrEquals(1);
enforce('a').longerThanOrEquals(1);
// passes
enforce([1]).longerThanOrEquals(2);
enforce('').longerThanOrEquals(1);
// throws

numberEquals​

Description​

Checks that your numeric enforced value is equals another value.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(0).numberEquals(0);
enforce(2).numberEquals('2');
// passes
enforce(100).numberEquals(10);
enforce('110').numberEquals(100);
enforce([0]).numberEquals(1);
// throws

numberNotEquals​

Description​

Checks that your numeric enforced value does not equal another value. Reverse implementation of numberEquals.

Arguments​

  • value: number | string | A numeric value against which you want to check your enforced value.

Strings are parsed using Number(), values which are not fully numeric always return false;

Usage​

enforce(2).numberNotEquals(0);
enforce('11').numberNotEquals('10');
// passes
enforce(100).numberNotEquals(100);
enforce('110').numberNotEquals(100);
// throws

shorterThan​

Description​

Checks that your enforced value is shorter than a given number.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([]).shorterThan(1);
enforce('a').shorterThan(2);
// passes
enforce([1]).shorterThan(0);
enforce('').shorterThan(0);
// throws

shorterThanOrEquals​

Description​

Checks that your enforced value is shorter than or equals a given number.

Arguments​

  • size: number | the number which you would like your initial value to be tested against.

The value argument can be of the following types:

  • array: checks against length.
  • string: checks against length.

Usage examples:​

enforce([]).shorterThanOrEquals(1);
enforce('a').shorterThanOrEquals(2);
enforce([]).shorterThanOrEquals(0);
enforce('a').shorterThanOrEquals(1);
// passes
enforce([1]).shorterThanOrEquals(0);
enforce('ab').shorterThanOrEquals(1);
// throws

matches​

Description​

Checks if a value contains a regex match.

Arguments​

  • regexp: either a RegExp object, or a RegExp valid string

Usage examples:​

enforce(1984).matches(/[0-9]/);
enforce(1984).matches('[0-9]');
enforce('1984').matches(/[0-9]/);
enforce('1984').matches('[0-9]');
enforce('198four').matches(/[0-9]/);
enforce('198four').matches('[0-9]');
// passes
enforce('ninety eighty four').matches(/[0-9]/);
enforce('ninety eighty four').matches('[0-9]');
// throws

notMatches​

Description​

Checks if a value does not contain a regex match. Reverse implementation of matches.

Usage examples:​

enforce(1984).notMatches(/[0-9]/);
// throws
enforce('ninety eighty four').notMatches('[0-9]');
// passes

inside​

Description​

Checks if your enforced value is contained in another array or string. Your enforced value can be of the following types:

  • string
  • number
  • boolean

Arguments​

  • container: a string or an array which may contain the value specified.

Usage examples:​

inside: array​

Checks for membership in an array.

  • string: checks if a string is an element in an array
enforce('hello').inside(['hello', 'world']);
// passes
enforce('hello!').inside(['hello', 'world']);
// throws
  • number: checks if a number is an element in an array
enforce(1).inside([1, 2]);
// passes
enforce(3).inside([1, 2]);
// throws
  • boolean: checks if a number is an element in an array
enforce(false).inside([true, false]);
// passes
enforce(true).inside([1, 2, 3]);
// throws

inside: string​

  • string: checks if a string is inside another string
enforce('da').inside('tru dat.');
// passes
enforce('ad').inside('tru dat.');
// throws

notInside​

Description​

Checks if a given value is not contained in another array or string. Reverse implementation of inside.

Usage examples:​

enforce('ad').notInside('tru dat.');
enforce('hello!').notInside(['hello', 'world']);
// passes
enforce('hello').notInside(['hello', 'world']);
enforce('da').notInside('tru dat.');
// throws

isTruthy​

Description​

Checks if a value is truthy; Meaning: if it can be coerced into boolean true. Anything not in the following list is considered to be truthy.

  • undefined
  • null
  • false
  • 0
  • NaN
  • empty string ("")

Usage examples:​

enforce('hello').isTruthy();
enforce(true).isTruthy();
enforce(1).isTruthy();
// passes
enforce(false).isTruthy();
enforce(null).isTruthy();
enforce(undefined).isTruthy();
enforce(0).isTruthy();
enforce(NaN).isTruthy();
enforce('').isTruthy();
// throws

isFalsy​

Description​

Checks if a value is falsy; Meaning: if it can be coerced into boolean false. Reverse implementation of isTruthy.

Anything not in the following list is considered to be truthy:

  • undefined
  • null
  • false
  • 0
  • NaN
  • empty string ("")

Usage examples:​

enforce(false).isFalsy();
enforce(0).isFalsy();
enforce(undefined).isFalsy();
// passes
enforce(1).isFalsy();
enforce(true).isFalsy();
enforce('hi').isFalsy();
// throws

isArray​

Description​

Checks if a value is of type Array.

Usage examples:​

enforce(['hello']).isArray();
// passes
enforce('hello').isArray();
// throws

isNotArray​

Description​

Checks if a value is of any type other than Array. Reverse implementation of isArray.

Usage examples:​

enforce(['hello']).isNotArray();
// throws
enforce('hello').isNotArray();
// passes

isBoolean​

Description​

Checks if a value is of type boolean. Equals typeof value === 'boolean'

Usage examples:​

enforce(true).isBoolean();
enforce(false).isBoolean();
enforce(!!0).isBoolean();
// passes
enforce([]).isBoolean();
enforce('143').isBoolean();
enforce('false').isBoolean();
// throws

isNotBoolean​

Description​

Checks if a value is of any type other than boolean. Reverse implementation of isBoolean.

Usage examples:​

enforce('143').isNotBoolean();
enforce(143).isNotBoolean();
// passes
enforce(true).isNotBoolean();
enforce(false).isNotBoolean();
// throws

isBlank​

Description​

Determines whether an enforced string contains only whitespaces. It will also check for null or undefined. All other values will return false - to not be confused with isEmpty.

Usage examples:​

enforce('   ').isBlank(); // passes
enforce('not blank').isBlank(); // throws

isNotBlank​

Description​

Determines whether an enforced string contains at least a non-whitespace character. Will also return true for null or undefined. Any other value will return true. This is the reverse of isBlank.

Usage examples:​

enforce('not blank').isNotBlank(); // passes
enforce('   ').isNotBlank(); // throws

isNumber​

Description​

Checks if a value is of type number. Equals typeof value === 'number'

Usage examples:​

enforce(143).isNumber();
enforce(NaN).isNumber(); // (NaN is of type 'number!')
// passes
enforce([]).isNumber();
enforce('143').isNumber();
// throws

isNotNumber​

Description​

Checks if a value is of any type other than number. Reverse implementation of isNumber.

note isNotNumber does not check for NaN value. For NaN values, use isNaN.

Usage examples:​

enforce('143').isNotNumber();
enforce(143).isNotNumber();
// passes
enforce(143).isNotNumber();
enforce(NaN).isNotNumber(); // throws (NaN is of type 'number!')
// throws

isNaN​

Description​

A wrapper around JavaScripts Number.isNaN() function. Checks if a value is NaN.

Usage examples:​

enforce(NaN).isNaN();
enforce('A' / 'B').isNaN();
// passes
enforce(null * null).isNaN(); // null*null = 0
enforce(200).isNaN();
enforce('1984').isNaN();
// throws

isNotNaN​

Description​

Reverse implementation of isNaN. Checks that a value is not NaN.

Usage examples:​

enforce(null * null).isNaN(); // null*null = 0
enforce(200).isNaN();
enforce('1984').isNaN();
// passes
enforce(NaN).isNaN();
enforce('A' / 'B').isNaN();
// throws

isNull​

Description​

Enforces that a specified value is null.

Usage examples:​

enforce(null).isNull();
// passes
enforce(undefined).isNull();
enforce(true).isNull();
// throws

isNotNull​

Description​

Reverse implementation of isNull. Checks that a value is not null.

Usage examples:​

enforce('hello').isNull();
enforce(200).isNull();
// passes
enforce(null).isNull();
// throws

isNullish​

Description​

Checks if a value is either null or undefined.

Usage examples:​

enforce(null).isNullish(); // passes
enforce(undefined).isNullish(); // passes
enforce('hello').isNullish(); // throws
enforce(200).isNullish(); // throws

isNotNullish​

Description​

Checks if a value is not null or undefined.

Usage examples:​

enforce('hello').isNotNullish(); // passes
enforce(200).isNotNullish(); // passes
enforce(null).isNotNullish(); // throws
enforce(undefined).isNotNullish(); // throws

isString​

Description​

Checks if a value is of type String.

Usage examples:​

enforce('hello').isString();
// passes
enforce(['hello']).isString();
enforce(1984).isString();
// throws

isNotString​

Description​

Checks if a value is of any type other than String. Reverse implementation of isString.

Usage examples:​

enforce('hello').isNotString();
// throws
enforce(['hello']).isNotString();
// passes

isUndefined​

Description​

Enforces that a given value is (===) undefined.

Usage examples:​

enforce().isUndefined();
enforce(undefined).isUndefined();
// passes
enforce(null).isUndefined();
enforce(true).isUndefined();
// throws

isOdd​

Description​

Checks if a value is an odd numeric value.

Usage examples:​

enforce('1').isOdd();
enforce(9).isOdd();
// passes
enforce(2).isOdd();
enforce('4').isOdd();
enforce('1withNumber').isOdd();
enforce([1]).isOdd();
// throws

isEven​

Description​

Checks if a value is an even numeric value.

Usage examples:​

enforce(0).isEven();
enforce('2').isEven();
// passes
enforce(1).isEven();
enforce('3').isEven();
enforce('2withNumber').isEven();
enforce([0]).isEven();
// throws

isBetween​

Description​

Checks if a number is in the range of two numbers (edges of range included)

Usage examples:​

enforce(5).isBetween(0, 5);
enforce(5).isBetween(0, 10);
enforce(-5).isBetween(-10, -1);
enforce(-5.5).isBetween(-10, -1);
enforce(-5.5).isBetween(-10, -1.1);
enforce(-5.5).isBetween(-9.5, -1.1);
// passes
enforce(5).isBetween(0, 2);
enforce(-5).isBetween(0, 2);
enforce('some_string').isBetween(0, 2);
enforce(false).isBetween(0, 2);
// throws

isNotBetween​

Description​

Checks if a number is not in range of two numbers (edges of range excluded)

Usage examples:​

enforce(5).isNotBetween(0, 4);
enforce(5).isNotBetween(0, 10);
enforce(-5).isNotBetween(-10, -1);
enforce(-5.5).isNotBetween(-10, -1);
enforce(-5.5).isNotBetween(-10, -1.1);
// passes
enforce(5).isNotBetween(0, 5);
enforce(5).isNotBetween(0, 10);
enforce(-5).isNotBetween(-10, -1);
enforce(-5).isNotBetween(-5, -1);
enforce('some_string').isNotBetween(0, 2);
enforce(false).isNotBetween(0, 2);
// throws

endsWith​

Description​

Determines whether a string ends with the characters of a specified string.

Usage examples:​

enforce('aba').endsWith('ba');
enforce('some_string').endsWith('_string');
enforce('string with spaces').endsWith('ng with spaces');
enforce('aaaa     ').endsWith(' ');
// passes
enforce('for').endsWith('tor');
enforce('aaaab').endsWith('aaaa');
enforce('aa').endsWith('aaa');
enforce(42).endsWith('b');
enforce(42).endsWith(50);
enforce(true).endsWith(100);
// throws

doesNotEndWith​

Description​

Determines whether a string does not end with the characters of a specified string. Reverse implementation of endsWith.

startsWith​

Description​

Determines whether a string starts with the characters of a specified string.

Usage examples:​

enforce('aba').startsWith('ab');
enforce('some_string').startsWith('some_');
enforce('string with spaces').startsWith('string with s');
enforce('aaaa     ').startsWith('aaaa ');
// passes
enforce('for').startsWith('tor');
enforce('aaaab').startsWith('aab');
enforce('aa').startsWith('aaa');
enforce(42).startsWith('b');
enforce(42).startsWith(50);
enforce(true).startsWith(100);
// throws

doesNotStartWith​

Description​

Determines whether a string does not start with the characters of a specified string. Reverse implementation of startsWith.

Usage examples:​

enforce('for').doesNotStartWith('tor');
enforce('aaaab').doesNotStartWith('aab');
enforce('aa').doesNotStartWith('aaa');
enforce(42).doesNotStartWith('b');
enforce(42).doesNotStartWith(50);
enforce(true).doesNotStartWith(100);
// passes
enforce('aba').doesNotStartWith('ab');
enforce('some_string').doesNotStartWith('some_');
enforce('string with spaces').doesNotStartWith('string with s');
enforce('aaaa     ').doesNotStartWith('aaaa ');
// throws

isNegative​

Description​

Determines whether a numeric value is negative or not.

Usage examples:​

enforce(-10).isNegative(); //passes
enforce(-10.12).isNegative(); //passes
enforce('-10.12').isNegative(); //passes
enforce(10).isNegative(); // throws
enforce('10').isNegative(); // throws
enforce(0).isNegative(); // throws

isPositive​

Description​

Determines whether a numeric value is positive or not.

Usage examples:​

enforce(10).isPositive(); //passes
enforce(10.12).isPositive(); //passes
enforce('10.12').isPositive(); //passes
enforce(-10).isPositive(); // throws
enforce('-10.12').isPositive(); // throws
enforce(0).isPositive(); // throws

isValueOf​

Description​

Determines whether a value exists as inside an object.

Usage examples:​

enforce('Bravo').isValueOf({ a: 'Alpha', b: 'Bravo', c: 'Charlie' });
// passes
enforce('Delta').isValueOf({ a: 'Alpha', b: 'Bravo', c: 'Charlie' });
// throws

isNotValueOf​

Description​

Determines whether a string is not a value of an object..

Usage examples:​

enforce('Delta').isNotValueOf({ a: 'Alpha', b: 'Bravo', c: 'Charlie' });
// passes
enforce('Bravo').isNotValueOf({ a: 'Alpha', b: 'Bravo', c: 'Charlie' });
// throws

isKeyOf​

Description​

Determines whether a value is a key of an object

Usage examples:​

enforce('bananas').isKeyOf({ bananas: 5 });
enforce(1976).isKeyOf({ 1976: 'Rocky' });

// passes
enforce('avocados').isKeyOf({ cantelopes: 5 });
enforce(1967).isKeyOf({ 1988: 'Rain Man' });
enforce('key').isKeyOf(undefined);
enforce(15).isKeyOf(null);
enforce('star').isKeyOf(false);
enforce('triangle').isKeyOf(true);
// throws

isNotKeyOf​

Description​

Determines whether a value is not a key of an object

Usage examples:​

enforce('avocados').isNotKeyOf({ cantelopes: 5 });
enforce(1967).isNotKeyOf({ 1988: 'Rain Man' });
enforce('key').isNotKeyOf(undefined);
enforce(15).isNotKeyOf(null);
enforce('star').isNotKeyOf(false);
enforce('triangle').isNotKeyOf(true);
// passes
enforce('bananas').isNotKeyOf({ bananas: 5 });
enforce(1976).isNotKeyOf({ 1976: 'Rocky' });
// throws