The best way to check if an array is empty in JavaScript is by using the Array.isArray() method (ES5+) and array's length property together like so: // ES5+ if (!Array.isArray(array) || !array.length) { /
If the value is an array, we return the result of calling thefiltermethod, otherwise, we return an empty array. This way, you won't get an error, even if the value is not an array. If the value is fetched from a remote server, make sure it is of the expected type by logging it...
If we consider an empty string consisting of only spaces, we can usetrim()the method to remove any leading or trailing spaces before checking whether the string is empty. conststr =' ';if(typeofstr ==='string'&& str.trim().length===0) {console.log('string is empty'); }else{consol...
Unwinding on a nonexistent property or a property whose value is not an array returns an empty array.Example:F.unwind('b', [{ a: true, b: [1, 2] }]) //=> [{ a: true, b: 1 }, { a: true, b: 2 }]unwindArrayk -> [{ k: [a, b] }] -> [{ k: a }, { k: b...
If we were creating an array, it would be an empty array. Next, we need to figure out what the parameters are for the function we pass to .reduce. In our example, we named them total and num. Remember, this function is going to be called for each element in the array. The reason...
is.empty(value:array|object|string) Checks if the given value is empty. is.existy(value:any) Checks if the given value is existy. (not null or undefined) is.truthy(value:any) Checks if the given value is truthy. (existy and not false) is.falsy(value:any) Checks if the given valu...
We can also check if a variable stores a truthy value. Truthful values are all values that are not false. Falsy values in JavaScript are:undefined,null,false, ,0,""(empty string),NaN(not a number). import{useEffect, useState}from'react'; ...
Adding an empty string to something is a useful way of converting it. Comparisonsin JavaScript can be made using<,>,<=and>=. These work for both strings and numbers. Equality is a little less straightforward. The double-equals operator performs type coercion if you give it different types,...
is.array(value:any) Checks if the given value type is array. interfaces: not, all, any is.array(['foo','bar','baz'])=>trueis.not.array({foo:'bar'})=>trueis.all.array(['foo'],'bar')=>falseis.any.array(['foo'],'bar')=>true// 'all' and 'any' interfaces can also take...
Here, if block checks if variable has a truthy value, so it will go to elseif block even if value is 0, $false, an empty String, an empty array, and not just $null, and that’s the reason, we have put explicit check in elseif statement if variable is $null. 5. Using Null-Co...