Because the concat method is less efficient than the + operator, it is recommended to use the latter instead. concat.js let a = 'old'; let c = a.concat(' tree'); console.log(c); The example concatenates two str
普通写法：我们通常使用Array中的concat()方法合并两个数组。用concat()方法来合并两个或多个数组，不会更改现有的数组，而是返回一个新的数组。请看一个简单的例子：let apples = ['', ''];let fruits = ['', '', ''].concat(apples);console.log( fruits );//=> ["", "", "", "", ""]简...
console.log("".concat(null)); // null console.log("".concat(true)); // true console.log("".concat(4, 5)); // 45 let str1 = "Hello"; let str2 = "World"; // concatenating two strings let newStr = str1.concat(", ", str2, "!"); console.log(newStr); // Hello, ...
x >= y // => false: greater-than or equal "two" === "three" // => false: the two strings are different "two" > "three" // => true: "tw" is alphabetically greater than "th" false === (x > y) // => true: false is equal to false // Logical operators combine or inv...
concat() Joins two or more strings. replace() Replace a string with another string. split() Converts the string to an array of strings. substr() Returns a part of a string by taking the starting position and length of the substring. substring() Returns a part of the string from the ...
JavaScript String concat() concat()joins two or more strings: Example lettext1 ="Hello"; lettext2 ="World"; lettext3 = text1.concat(" ", text2); Try it Yourself » Theconcat()method can be used instead of the plus operator. These two lines do the same: ...
Concatenate strings and numbers: constarr1 = ["Cecilie","Lone"]; constarr2 = [1,2,3]; constarr3 = arr1.concat(arr2); Try it Yourself » Concatenate nested arrays: constarr1 = [1,2, [3,4]]; constarr2 = [[5,6],7,8]; ...
我们通常使用Array中的concat()方法合并两个数组。用concat()方法来合并两个或多个数组,不会更改现有的数组,而是返回一个新的数组。请看一个简单的例子: let apples = [' ', ' ']; let fruits = [' ', ' ', ' '].concat(apples); console.log( fruits ); ...
There is a built-in String method that can concatenate multiple strings: concat. It takes one or more string parameters, each of which are appended to the end of the string object: var nwStrng = "".concat("This ","is ","a ","string"); // returns "This is a string" The concat...
Tho it is hard for JS developers like me to use the V8 trace to find where in their code the string concat (or other) happened. Do you have any tech talks, blogs, or docs that would help devs like me correctly read the trace?