jquery/javascript check string for multiple substrings

if (/term1|term2|term3/.test("your string")) {
   //youre code
}

This achieves dynamically and elegantly what you are trying to do

const terms = ["term1", "term2", "term3"]
const str = "very large string to check for term1, tern2, etc ..."

// check if the string has some of the terms
const result1 = terms.some(term => str.includes(term))

// check if the string has all the terms
const result2 = terms.every(term => str.includes(term))

This also makes it easy to filter an array of strings for an array of substrings

const terms = ["term1", "term2", "term3"]
const strings = ["very large string text ....", "another large string text"] 

// filter the strings of the array that contain some of the substrings we're looking for
const result1 = strings.filter(str => terms.some(term => str.includes(term)))

// filter the strings of the array that contain all the substrings we're looking for
const result2 = strings.filter(str => terms.every(term => str.includes(term)))

You could use a loop. Maybe even create a helper function like so:

function ContainsAny(str, items){
    for(var i in items){
        var item = items[i];
        if (str.indexOf(item) > -1){
            return true;
        }

    }
    return false;
}

Which you can then call like so:

if(ContainsAny(str, ["term1", "term2", "term3"])){
   //do something
}

The .map() function can be used to convert an array of terms into an array of booleans indicating if each term is found. Then check if any of the booleans are true.

Given an array of terms:

const terms = ['term1', 'term2', 'term3'];

This line of code will return true if string contains any of the terms:

terms.map((term) => string.includes(term)).includes(true);       

Three examples:

terms.map((term) => 'Got term2 here'.includes(term)).includes(true);       //true
terms.map((term) => 'Not here'.includes(term)).includes(true);             //false
terms.map((term) => 'Got term1 and term3'.includes(term)).includes(true);  //true

Or, if you want to wrap the code up into a reusable hasTerm() function:

const hasTerm = (string, terms) =>
   terms.map(term => string.includes(term)).includes(true);

hasTerm('Got term2 here', terms);       //true
hasTerm('Not here', terms);             //false
hasTerm('Got term1 and term3', terms);  //true

Try it out:
https://codepen.io/anon/pen/MzKZZQ?editors=0012

.map() documentation:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

Note: This answer optimizes for simplicity and readability. If extremely large arrays of terms are expected, use a loop that short-circuits once a term is found.

Maybe this:

if (str.indexOf("term1") >= 0 || str.indexOf("term2") >= 0 || str.indexOf("term3") >= 0) 
{
 //your code
}

You can do something like

function isSubStringPresent(str){
    for(var i = 1; i < arguments.length; i++){
        if(str.indexOf(arguments[i]) > -1){
            return true;
        }
    }

    return false;
}

isSubStringPresent('mystring', 'term1', 'term2', ...)

If you want to check for multiple string matches and highlight them, this code snippet works.

function highlightMatch(text, matchString) {
    let textArr = text.split(' ');
    let returnArr = [];
    
    for(let i=0; i<textArr.length; i++) {
        let subStrMatch = textArr[i].toLowerCase().indexOf(matchString.toLowerCase());
        
        if(subStrMatch !== -1) {
            let subStr = textArr[i].split('');
            let subStrReturn = [];
            
            for(let j=0 ;j<subStr.length; j++) {
                
                if(j === subStrMatch) {
                    subStrReturn.push('<strong>' + subStr[j]);    
                } else if (j === subStrMatch + (matchString.length-1)){
                    subStrReturn.push(subStr[j] + '<strong>');
                } else {
                    subStrReturn.push(subStr[j]);
                }
            }
            returnArr.push(subStrReturn.join(''));
        } else {
            returnArr.push(textArr[i]);
        }
    }
    return returnArr;
}


highlightMatch('Multi Test returns multiple results', 'multi'); 
=>  (5) ['<strong>Multi<strong>', 'Test', 'returns', '<strong>multi<strong>ple', 'results']