Is there a javascript method to find substring in an array of strings?

var array= ["abcdefg", "hijklmnop"];
var newArray = array.filter(function(val) {
    return val.indexOf("mnop") !== -1
})
console.log(newArray)

a possible solution is filtering the array through string.match

var array= ["abcdefg", "hijklmnop"];

var res = array.filter(x => x.match(/mnop/));

console.log(res)

You can use Array#some:

// ES2016
array.some(x => x.includes(testString));

// ES5
array.some(function (x) {
  return x.indexOf(testString) !== -1;
});

Note: arrow functions are part of ES6/ES2015; String#includes is part of ES2016.

The Array#some method executes a function against each item in the array: if the function returns a truthy value for at least one item, then Array#some returns true.

Javascript does not provide what you're asking before because it's easily done with existing functions. You should iterate through each array element individually and call indexOf on each element:

array.forEach(function(str){
    if(str.indexOf("mnop") !== -1) return str.indexOf("mnop");
});

Can be done like this https://jsfiddle.net/uft4vaoc/4/

Ultimately, you can do it a thousand different ways. Almost all answers above and below will work.

<script>
var n;
var str;
var array= ["abcdefg", "hijklmnop"];
//console.log(array.indexOf("mnop")); //-1 since it does not find it in the string
for (i = 0; i < array.length; i++) { 
    str = array[i];
    n = str.includes("mnop");
    if(n === true){alert("this string "+str+" conatians mnop");}
}
</script>