Strings

You can place " double quotes directly into ' single quote strings.

var sampleText = 'She came in and said "Good Morning." to everyone.';

You can place " double quotes inside " double quotes by escaping them.

var sampleText = "She came in and said \"Good Morning.\" to everyone.";

You can use the += operator to concatenate and assign the string result.

var text = 'Some text.';
text += ' And some more text.'; // => 'Some text. And some more text.'

You can ** get the length of a string** using the string length function.

'Hello'.length; // => 5

The contents of strings are immutable. This immutability refers only to the actual string object NOT the reference to the string. In the example below you can see that trying to change a string character by index leaves the value of text unchanged because the string is immutable. However the text variable that points to the string IS mutable and can be reassigned to a new string object entirely.

var text = 'Bob';
text[0] = 'J'
text // => 'Bob' - string not changed
text = 'Job'
text // => 'Job' - text reassigned to a new immutable string

You can return a specific sub-string character of a string by appending [ ] square brackets to its end as if it were an array and placing the index of the character you want to output.

'Hello'[0]; // => 'H'

You can interpolate variables into a string by surrounding your string with back-ticks and using a ${ } symbol inside the string with the variable you want to interpolate placed between the curly brackets.

var name = 'Dec';
console.log(`My name is ${name}.`);

You cannot multiply strings in Javascript. For example, 'd' * 5 is not valid syntax for outputting 'ddddd', instead you should use the repeat method on a string to duplicate it. This returns the duplicated string.

// with var
var letter = 'd'
letter.repeat(5) // => 'ddddd'
// directly in a string
'd'.repeat(5) // => 'ddddd'

You can replace all occurrences of a set of characters in a string using regular expression paired with the replace function with the g flag appended to the end of the regex. The + regex modifier does not work for this functionality in javascript.

"some* string}[& with^ w#eird stuff$$ in@".replace(/[^a-z\s]/g, '')
// => 'some string with weird stuff in'