Let’s pretend that JavaScript has a triple dot operator (...) that turns arrays into actual parameters. Such an operator would allow you to use Math.max() (see Other Functions) with arrays. In that case, the following two expressions would be equivalent: Math.max(...[13, 7, 30]) ...
“Unexpected early end of program.”:“程序不可预期的提前终止”, “A leading decimal point can be confused with a dot: ‘.{a}’.”:“‘{a}’前的点容易混淆成小数点”, “Use the array literal notation [].”:“使用数组的符号 []“, “Expected an operator and instead saw ‘{a}’.”...
JavaScript中的属性访问器使用点(。)或方括号([]),但不能同时使用两者。方括号允许计算属性访问。 代码语言:javascript 复制 varobj={foo:{bar:"baz",bar2:"baz2"}};vari=2;obj.[foo].[bar]// SyntaxError: missing name after . operatorobj.foo."bar"+i;// SyntaxError: missing name after . opera...
A triple equals sign (===) is used to compare two values (seeEquality Operators). Comments There are two kinds of comments: Single-line comments via//extend tothe rest of the line. Here’s an example: vara=0;// init Multiline comments via/* */can extend over arbitraryranges of text...
{ parse: { // parse options }, compress: { // compress options }, mangle: { // mangle options properties: { // mangle property options } }, format: { // format options (can also use `output` for backwards compatibility) }, sourceMap: { // source map options }, ecma: 5, // ...
11.What does it mean that JavaScript has First-class functions? 12.What is a higher-order function? 13.Are concepts of higher-order function and closure connected? 14.What is the difference between arrow functions and the regular functions?
在这段代码中,展开操作符 (spread operator) 并没有按预期的方式执行:而是先将多个解构变为剩余参数 (rest parameter), 然后再将剩余参数展开为字面量对象。 只能用于可迭代对象 在数组或函数参数中使用展开语法时,该语法只能用于 可迭代对象: jsCopy to Clipboard var obj = { key1: "value1" }; var arra...
To avoid type coercion, use the triple-equals operator: 1 2 123 === '123'; // false 1 === true; // false There are also != and !== operators. JavaScript also has bitwise operations. If you want to use them, they're there. Control structures JavaScript has a similar set of con...
To avoid type coercion, use the triple-equals operator: > 1 === true false > true === true true There are also != and !== operators. JavaScript also has bitwise operations. If you want to use them, they're there. [edit] Control structures ...
That’s right, === is also a boolean operator. == or ===? In most languages == (double equals) means equal to. In JavaScript === (triple equals) means exactly equals to and == means equal to with type casting. Type casting is fiddly stuff, and often behaves in unexpected ways....