Convert string to Pascal Case (aka UpperCamelCase) in Javascript

Question

Id like to know how I can covert a string into a pascal case string in javascript (& most probally regex).

Conversion Examples:

• double-barrel = Dou

Answer 1

Here's my suggestion:

function toPascalCase(string) {
  return `${string}`
    .replace(new RegExp(/[-_]+/, 'g'), ' ')
    .replace(new RegExp(/[^\w\s]/, 'g'), '')
    .replace(
      new RegExp(/\s+(.)(\w+)/, 'g'),
      ($1, $2, $3) => `${$2.toUpperCase() + $3.toLowerCase()}`
    )
    .replace(new RegExp(/\s/, 'g'), '')
    .replace(new RegExp(/\w/), s => s.toUpperCase());
}

or

String.prototype.toPascalCase = function() {
  return this
    .replace(new RegExp(/[-_]+/, 'g'), ' ')
    .replace(new RegExp(/[^\w\s]/, 'g'), '')
    .replace(
      new RegExp(/\s+(.)(\w+)/, 'g'),
      ($1, $2, $3) => `${$2.toUpperCase() + $3.toLowerCase()}`
    )
    .replace(new RegExp(/\s/, 'g'), '')
    .replace(new RegExp(/\w/), s => s.toUpperCase());
};

Test cases:

describe('String to pascal case', function() {
  it('should return a pascal cased string', function() {
    chai.assert.equal(toPascalCase('foo bar'), 'FooBar');
    chai.assert.equal(toPascalCase('Foo Bar'), 'FooBar');
    chai.assert.equal(toPascalCase('fooBar'), 'FooBar');
    chai.assert.equal(toPascalCase('FooBar'), 'FooBar');
    chai.assert.equal(toPascalCase('--foo-bar--'), 'FooBar');
    chai.assert.equal(toPascalCase('__FOO_BAR__'), 'FooBar');
    chai.assert.equal(toPascalCase('!--foo-¿?-bar--121-**%'), 'FooBar121');
  });
});