Declare (create) stringsDeclare (create) numbersDeclare (create) an arrayDeclare (create) an objectFind the type of a variableAdding two numbers and a stringAdding a string and two numbersAn undefined variableAn empty variable JavaScript Objects ...
>typeoftrue'boolean'>typeof'abc''string'>typeof{}// empty object literal'object'>typeof[]
DECLARE @sysname sysname; --数据库名称变量 DECLARE My_Cursor CURSOR --定义游标 FOR (select [name] from [master].[dbo].[sysdatabases]) --查出所有的数据库名称的集合放到游标中 OPEN My_Cursor; --打开游标 FETCH NEXT FROM My_Cursor INTO @sysname; --读取下一行/第一行数据并存放在变量值中 WH...
letempty = {};// An object with no propertiesletpoint = {x:0,y:0};// Two numeric propertiesletp2 = {x: point.x,y: point.y+1};// More complex valuesletbook = {"main title":"JavaScript",// These property names include spaces,"sub-title":"The Definitive Guide",// and hyphens...
new Object()→ {} String(exp) or exp.toString()→ "" + exp new Object/RegExp/Function/Error/Array (...)→ we discard the new "foo bar".substr(4)→ "bar" Conditional compilation You can use the --define (-d) switch in order to declare global variables that Terser will assume to...
varxy=Object;// Declare empty objectxy["x"]=100;xy["y"]=200;log(JSON.stringify(xy));log(xy["z"]); output: {x:100,y:200}undefined Object literal notation: varo=(Obj"x",100,"y",400);log(JSON.stringify(o)); output:
// if target value and source value has same type but not object, assign directly else if (targetValueType === sourceValueType) { target[key] = value } } } function mergeArray(sourceArray, targetArray) { // the rule of array merge need additional declare, assume the target already ...
-2 JavaScript How to declare 16 length array with default 0 value quick? 1 How to create an array in JS that is initialized to 0? 0 What is a javascript "[ <3 empty items> ]" structure? 0 Does setting array length during the creation give benefits? See more linked questions Rela...
First, assign to keys on the free variable exports to declare your module’s public API: 'use strict'; var foo = function foo () { return true; }; exports.foo = foo; Then use require() to import your module and assign it to a local variable. You can specify the name of a modul...
It is a common practice to declare arrays with theconstkeyword. Learn more aboutconstwith arrays in the chapter:JS Array Const. Example constcars = ["Saab","Volvo","BMW"]; Try it Yourself » Spaces and line breaks are not important. A declaration can span multiple lines: ...