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Strings

Description

JavaScript String Data Type

Usage

let codeString = "perl";
let stackString = "LAMP uses ${codeString}";

Index

  • string index, char position in string, starts at 0

Multi-Line String

let newString = `
    This string spans
    more than one line`;  // Backticks
let anotherString = "A line that \
spans two lines";  // Backslash
let recommendedMethod = "Use the concatenatiion" +
'operator which has wider browser support";

Concatenator Operator

let a = 'hello,';
let b = ' there';
a + b; 'hello, there'

length Prop

const stringA = "Circle";
let stringLen = stringA.length; // 6

Escaping Chars

string0 = "This is a single quote: \'"; 
string1 = "This is a double quote: \"";  
string2 = "This is a backslash: \\";

substring Method

let result = targetString.substring(startIndex , endIndex);
let phoneNumberA = "1-800-555-5555"; // 14 chars
let phoneNumberB = "555-123-5555"; // 12 digits
let lenA = phoneNumberA.length; 
let lastFourDigits = phoneNumberA.substring(lenA - 4, lenA);

toUpperCase() toLowerCase() Methods

  • converts entire string
let actionWord = actionWord.toUpperCase() + "!";

indexOf() Method

  • Returns -1, or index of 1st match
let targetString = "0123456789";
let digitIndex = targetString.indexOf('5');  // 5

replace() Method

  • Removes searched for subString, inserts new subString at index of old
let newString = originalString.replace("gray", "grey");
let newString = originalString.replace("colour", "color");

trim() Method

let noBookendWhiteSpaceString = messyString.trim();

charAt() Method

  • Returns empty string, or char located at index
let charAtIndex = targetString[10];
Return "\"" + charAtIndex + "\" is the tenth char.";

localeCompare() Method

  • Returns the difference of ASCII vals
let firstString = "IDK";
let secondString = "IDK";
Return secondString.localeCompare(firstString); // 0 or IDK

String Object

let stringObject = new String("Cello");

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