let myString = new String("John Doe"); if (_.isString(myString)) { console.log("This variable is a string"); } else { console.log("This variable is not a string"); } Output: This variable is a string Conclusion In this article, we've learned how to check if a variable is...
str3 = new String('Great Place'); Now to check whether a given variable is a string or not, we'll use a JavaScript operator calledtypeof. Syntax: typeof variable; This operator returns the data type of the variable specified after it. If the variable is of string data type, it will...
* @param {Object} value 元素值 */function isInArray(arr,value){ var index = $.inArray(value,arr); if(index >= 0){ return true; } return false; } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 方法六、include()方法: arr.includes(searchElement)方法用来判断一个数组是否包含一个指定...
Step 1: We have to find out if the given string is a palindrome or not. So to do this task we will create a function called isPalindrome and in this function, we will pass a parameter of string as str. So for this str, we will check the palindrome condition. Step 2: After the...
// Check if variable is equal to value if (username === "sammy_shark") { console.log(true); } 输出: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 true 如前所述,变量可以用来表示任何JavaScript数据类型。在本例中,我们将使用字符串、数字、对象、布尔值和null值声明变量。 代码语言:javascr...
The String.includes() Method This method was introduced in ES6 and is typically the preferred method for simple use-cases. If all you need to do is get a boolean value indicating if the substring is in another string, then this is what you'll want to use. It works like this: > let...
log(check(s)); Output typeof vs instanceof: Feature typeof instanceof Purpose Checks the type of a value Checks if an object is an instance of a class/constructor String Literal "string" false String Object "object" trueMayank Agarwal Updated on:...
arr.flatMap(function callback(currentValue[, index[, array]]) {}[, thisArg]) 代码语言:javascript 代码运行次数:0 运行 AI代码解释 let string = ["Hello","World"] string.flatMap( o => o.split("")).forEach(o =>console.log('out :%s',o)) === out :H out :e out :l out :l ...
In JavaScript, it's not always as straightforward as it should be to reliably check if a value is a number. It's common for devs to use+,-, orNumber()to cast a string value to a number (for example, when values are returned from user input, regex matches, parsers, etc). But the...
If the value exists, then the function will return the index value of the element, else it will return -1 Syntax put-array-or-string-here.indexOf() Code //code to check if a value exists in an array using javascript indexOf var fruits_arr = ['Apple', 'Mango', 'Grapes', '...