// Search through string's characters one by one. // If character is in bag, append to returnString. for (i = 0; i < s.length; i++) { // Check that current character isn't whitespace. var c = s.charAt(i); if (bag.indexOf(c) == -1) return false; } return true; } f...
The str is a variable. It returns false for null, undefined, 0, 000, "" and false. It returns true for not empty string and whitespace.Example:let str1 = 'Hello world!'; let str2 = ''; console.log(!!str1) console.log(!!str2) console.log(Boolean(str1)) console.log(Boolean(...
isBoolean Check if a string is a boolean. isCase(val, case) Check if the string is a cases. lower, upper, camel, pascal isColorCode(val, colorCode) Check if the string is a color code. rgb, hex, hsl isCreditCard(val, cardType) Check if the string is a credit card number. The...
1.1 Primitives: When you access a primitive type you work directly on its value. string number boolean null undefined symbol bigint const foo = 1; let bar = foo; bar = 9; console.log(foo, bar); // => 1, 9 Symbols and BigInts cannot be faithfully polyfilled, so they should not...
// JavaScript's most important datatype is the object.// An object is a collection of name/value pairs, or a string to value map.letbook={// Objects are enclosed in curly braces.topic:"JavaScript",// The property "topic" has value "JavaScript."edition:7// The property "edition" has...
以下两个if条件永远不应该为true,因为ownDesc和existingDesc应该相等: 如果existingDescriptor指定了一个访问器,则返回false。 如果existingDescriptor.[[Writable]]是false,则返回false。 返回Receiver.[[DefineOwnProperty]](P, { [[Value]]: V })。这个内部方法执行定义,我们用它来改变属性Receiver[P]的值。定义...
Missing quote marks. Astringis a series of characters enclosed by quote marks (you’ll learnabout these in greater detail onTypes of Data). For example,‘hello’is a string in the codealert(‘hellO’);. It’s easy to forget either the opening or closing quote mark. It’s also easy ...
Container.getBaseName() returns the base name of a file or folder, not including its parent folder, but including its extension. In the above example, f.getBaseName() would return the string "index.js". Container.getStem() is similar to Container.getBaseName(), but it does not include the...
pNd (DOM Node | string ID | Array) Parameters Array $u_Narray(pNd) Given a DOM node or string ID or an array (pNd), this function returns a single value, if an pNd is an array but only has one element the value of that element will be returned otherwise the array will be return...
pNd (DOM Node | string ID | Array) Parameters Array $u_Narray(pNd) Given a DOM node or string ID or an array (pNd), this function returns a single value, if an pNd is an array but only has one element the value of that element will be returned otherwise the array will be return...