match

RegExp → String → [String | Undefined]

Parameters

• rxA regular expression.
• strThe string to match against

Returns Array The list of matches or empty array.

Added in v0.1.0

Tests a regular expression against a String. Note that this function will return an empty array when there are no matches. This differs from String.prototype.match which returns null when there are no matches.

See also test.

R.match(/([a-z]a)/g, 'bananas'); //=> ['ba', 'na', 'na']
R.match(/a/, 'b'); //=> []
R.match(/a/, null); //=> TypeError: null does not have a method named "match"

split

(String | RegExp) → String → [String]

Parameters

• sepThe pattern.
• strThe string to separate into an array.

Returns Array The array of strings from str separated by sep.

Added in v0.1.0

Splits a string into an array of strings based on the given separator.

See also join.

const pathComponents = R.split('/');
R.tail(pathComponents('/usr/local/bin/node')); //=> ['usr', 'local', 'bin', 'node']
R.split('.', 'a.b.c.xyz.d'); //=> ['a', 'b', 'c', 'xyz', 'd']

trim

String → String

Parameters

• strThe string to trim.

Returns String Trimmed version of str.

Added in v0.6.0

Removes (strips) whitespace from both ends of the string.

R.trim('   xyz  '); //=> 'xyz'
R.map(R.trim, R.split(',', 'x, y, z')); //=> ['x', 'y', 'z']

replace

RegExp|String → String → String → String

Parameters

• patternA regular expression or a substring to match.
• replacementThe string to replace the matches with.
• strThe String to do the search and replacement in.

Returns String The result.

Added in v0.7.0

Replace a substring or regex match in a string with a replacement.

The first two parameters correspond to the parameters of the String.prototype.replace() function, so the second parameter can also be a function.

R.replace('foo', 'bar', 'foo foo foo'); //=> 'bar foo foo'
R.replace(/foo/, 'bar', 'foo foo foo'); //=> 'bar foo foo'
// Use the "g" (global) flag to replace all occurrences:
R.replace(/foo/g, 'bar', 'foo foo foo'); //=> 'bar bar bar'

toLower

String → String

Parameters

• strThe string to lower case.

Returns String The lower case version of str.

Added in v0.9.0

The lower case version of a string.

See also toUpper.

R.toLower('XYZ'); //=> 'xyz'

toUpper

String → String

Parameters

• strThe string to upper case.

Returns String The upper case version of str.

Added in v0.9.0

The upper case version of a string.

See also toLower.

R.toUpper('abc'); //=> 'ABC'

test

RegExp → String → Boolean

Parameters

• pattern
• str

Returns Boolean

Added in v0.12.0

Determines whether a given string matches a given regular expression.

See also match.

R.test(/^x/, 'xyz'); //=> true
R.test(/^y/, 'xyz'); //=> false

toString

* → String

Added in v0.14.0

Returns the string representation of the given value. eval‘ing the output should result in a value equivalent to the input value. Many of the built-in toString methods do not satisfy this requirement.

If the given value is an [object Object] with a toString method other than Object.prototype.toString, this method is invoked with no arguments to produce the return value. This means user-defined constructor functions can provide a suitable toString method. For example:

function Point(x, y) {
  this.x = x;
  this.y = y;
}
Point.prototype.toString = function() {
  return 'new Point(' + this.x + ', ' + this.y + ')';
};
R.toString(new Point(1, 2)); //=> 'new Point(1, 2)'
R.toString(42); //=> '42'
R.toString('abc'); //=> '"abc"'
R.toString([1, 2, 3]); //=> '[1, 2, 3]'
R.toString({foo: 1, bar: 2, baz: 3}); //=> '{"bar": 2, "baz": 3, "foo": 1}'
R.toString(new Date('2001-02-03T04:05:06Z')); //=> 'new Date("2001-02-03T04:05:06.000Z")'