可以使用String作为toString()更可靠的代替方法,因为它在用于null和undefined时仍然有效。例如: js constnullVar=null;nullVar.toString();// TypeError: nullVar is nullString(nullVar);// "null"constundefinedVar=undefined;undefinedVar.toString();// TypeError: undefinedVar is undefinedString(undefinedVar);/...
jsCopy to Clipboard const text = "Mozilla"; console.log(text.substring(5, 2)); // "zil" console.log(text.slice(5, 2)); // "" 如果两个参数中的任何一个或两个都是负数或 NaN,substring() 方法将把它们视为 0。 jsCopy to Clipboard console.log(text.substring(-5, 2)); // "Mo"...
jsCopy to Clipboard concat(str1) concat(str1, str2) concat(str1, str2, /* …, */ strN) 参数 str1、……、strN 要连接到 str 的一个或多个字符串。尽管技术上允许,但不带参数地调用 String.prototype.concat() 毫无意义,因为它不会(像 Array.prototype.concat())返回可观察的拷贝——字符串...
varstr="foo";str.prop="bar";alert(str.prop);// undefinedvarstr=newString("foo");str.prop="bar";alert(str.prop);// "bar" StackOverflow: What's the point of new String(“x”) in JavaScript? #Community Input @MaxStalker:I would use a different method depending on the application: ...
The length of the string in UTF-16 code units.# Methodsfunction at(pos: i32): string Gets the UTF-16 code unit at the specified position as a single character string. This method allows for positive and negative integers. Negative integers count back from the last string character. ...
Different methods to check if string contains spaces in JavaScript Method-1: UseindexOfmethod Not to be confused with the arrayindexOfmethod, theString.prototype.indexOf()takes a string argument and searches for it within the string it’s called upon and returns the index of the first occurren...
The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present. fromIndex可选,表示从这个位置开始搜索,若缺省或格式不合要求,使用默认值0. indexOf()方法返回给定元素能找在数组中找到的第一个索引值,如果没有找到,则返回-1。 mdn ...
If you need to get the number from the end of the string, use theString.match()method with the same regular expression. index.js functionendsWithNumber(str){return/[0-9]+$/.test(str);}functiongetNumberAtEnd(str){if(endsWithNumber(str)){returnNumber(str.match(/[0-9]+$/)[0]);}...
The String.fromCodePoint() static method returns a string created from the specified sequence of code points.
You know String.prototype.replace() in JavaScript? This method takes two parameters: pattern and replacement. Pattern is usually a string or regular expression. Technically it can be any object with a Symbol.replace method (like a RegExp). Replacement is either a string or function that returns...