Find whether an array has a substring corresponding to another element in a new array JS

Question

I get the value of "name" from a promise and I store it in an array as it MAY contain multiple names.

var name = ["Arun_Manohar"];
var combinations = ["abc", "def", "ghi", "har", "lmn"];

Lets say I have an activities object.

var activities = {
 driving: false,
 jogging: false,
 drinking: false
}

How do I go about writing a check to update the activities object in this case. NOTE: No two elements in combinations array will be a substring of names array. Just one.

Case: Since name contains a substring of one of the elements of combinations, I need to update the activities object. If the name contains a substring like "abc", I will update the object with different values.

Use of lodash would be great.

Tried something and wasnt able to update the object.

if(name.indexOf(_.filter(combinations, function(e) { return.indexOf("har") !== -1})) !== -1) {
 activities.driving= true;
 activities.jogging= true;
}

If the name contains "abcpoc", since the substring is present in combinations array, I update the object with a different set of values.

• Barmar: I don't understand, what does the activities object have to do with the two arrays?
• arunmmanoharan: Its nothing related to do with it. I just want to know how it might work.
• Barmar: You say you want to update the activities object. Update it with what?
• Barmar: Loop through the two arrays, using indexOf() to test if the substring is found. If it is, update activities.
• arunmmanoharan: @Barmar If its a substring that matches with "Arun_manohar" like "har", then I update the value of driving and jogging to be true

Answer 1

If you're using lodash, you can use _.intersectionWith, using a comparator function that uses indexOf().

matched_combos = _.intersectionWith(combinations, names, (combo, name) => name.indexOf(combo) != -1);

Then you can loop through matched_combos to add appropriate things to activities:

matched_combos.forEach(str => {
 switch(str) {
 "har":
 activities.driving = true;
 activities.jogging = true;
 break;
 ...
 }
});

Answer 2

var names = ["Arun_Manohar"];
var combos = ["abc", "def", "ghi", "har", "lmn"];
var activities = {};
for (var i = 0; i < names.length; i++) {
 for (var j = 0; j < combos.length; j++) {
 if (names[i].indexOf(combos[j]) >= 0) {
 activities.driving = true; //or whatever you need here;
 }
 }
}

Yo can also extend this code with additional checks and continue/break statements to avoid additional unnecessary loops if corresponding substring was already found.

• arunmmanoharan: Hey Artem, is there a way I can give the value of an element in the combinations array for the check? Like since "har" is present I update the object. If the names array is ["abcpoc"], and since "abc" is present, I want to update the object with a different set of values.
• Artem Arkhipov: which element do you mean?
• arunmmanoharan: Element in the sense an item in the array.
• Barmar: @a2441918 If you're looking for a specific string like "har", why do you need the combinations array?
• Artem Arkhipov: Actually names[i] is and element from names array and combos[j] is an element from combos array. You can do any check you need with those values.

Answer 3

Here is ES5 solution with indexOf:

var names = ["Arun_Manohar"];
var combinations = ["abc", "def", "ghi", "har", "lmn"];
var activities = {
 driving: false,
 jogging: false,
 drinking: false
}
for (var i = 0; i < names.length; i++) {
 for (var j = 0; j < combinations.length; j++) {
 if(names[i].indexOf(combinations[j]) >= 0) {
 activities.name = names[i]
 }
 }
}
console.log(activities);

And here is ES6 solution with includes:

var names = ["Arun_Manohar"];
var combinations = ["abc", "def", "ghi", "har", "lmn"];
var activities = {
 driving: false,
 jogging: false,
 drinking: false
}
for (var i = 0; i < names.length; i++) {
 for (var j = 0; j < combinations.length; j++) {
 if(names[i].includes(combinations[j])) {
 activities.name = names[i]
 }
 }
}
console.log(activities);

And here is more elegant ES6 solution with includes, forEach iterating method and arrow functions:

var names = ["Arun_Manohar"];
var combinations = ["abc", "def", "ghi", "har", "lmn"];
var activities = {
 driving: false,
 jogging: false,
 drinking: false
}
names.forEach(item1 => {
 combinations.forEach(item2 => {
 if(item1.includes(item2)) {
 activities.name = item1;
 }
 });
});
console.log(activities);