is string javascript
function isString(value) { return typeof value === 'string' || value instanceof String; } isString(''); // true isString(1); // false isString({}); // false isString([]); // false isString(new String('teste')) // true
is string javascript
function isString(value) { return typeof value === 'string' || value instanceof String; } isString(''); // true isString(1); // false isString({}); // false isString([]); // false isString(new String('teste')) // true
js string methods
JS String Methods: charAt() Returns a character at a specified position inside a string charCodeAt() Gives you the unicode of character at that position concat() Concatenates (joins) two or more strings into one fromCharCode() Returns a string created from the specified sequence of UTF-16 code units indexOf() Provides the position of the first occurrence of a specified text within a string lastIndexOf() Same as indexOf() but with the last occurrence, searching backwards match() Retrieves the matches of a string against a search pattern replace() Find and replace specific text in a string search() Executes a search for a matching text and returns its position slice() Extracts a section of a string and returns it as a new string split() Splits a string object into an array of strings at a specified position substr() Similar to slice() but extracts a substring depended on a specified number of characters substring() Also similar to slice() but can’t accept negative indices toLowerCase() Convert strings to lowercase toUpperCase() Convert strings to uppercase valueOf() Returns the primitive value (that has no properties or methods) of a string object
js string
`hello world` `hello! world!` `hello ${who}` escape `<a>${who}</a>`
Strings in javascript
var abc = "abcdefghijklmnopqrstuvwxyz"; var esc = 'I don\'t \n know'; // \n new line var len = abc.length; // string length abc.indexOf("lmno"); // find substring, -1 if doesn't contain abc.lastIndexOf("lmno"); // last occurance abc.slice(3, 6); // cuts out "def", negative values count from behind abc.replace("abc","123"); // find and replace, takes regular expressions abc.toUpperCase(); // convert to upper case abc.toLowerCase(); // convert to lower case abc.concat(" ", str2); // abc + " " + str2 abc.charAt(2); // character at index: "c" abc[2]; // unsafe, abc[2] = "C" doesn't work abc.charCodeAt(2); // character code at index: "c" -> 99 abc.split(","); // splitting a string on commas gives an array abc.split(""); // splitting on characters 128.toString(16); // number to hex(16), octal (8) or binary (2)
js string
String(thing)
js string methods
// String methods: 'hello'.toUpperCase(); // "HELLO"; 'LOL'.toLowerCase(); // "lol" ' omg '.trim(); // "omg" // String methods with arguments: // ============================== //indexOf returns the index where the character is found (or -1 if not found) 'spider'.indexOf('i'); //2 'vesuvius'.indexOf('u'); //3 - only returns FIRST matching index 'cactus'.indexOf('z'); //-1 not found // slice - returns a "slice" of a string "pancake".slice(3); //"cake" - slice from index 3 onwards "pancake".slice(0, 3); //"pan" - slice from index 0 up to index 3 // replace - returns a new string, with the FIRST match replaced "pump".replace("p", "b"); //"bump" - only replaces first "p" // String Template Literals // Use backtick characters, NOT SINGLE QUOTES!
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