Javascript: How do I check if an array contains exactly another array?

Question

Suppose I have arrays parent and child. I want to check if a child exists inside a parent array. The ordering matters.
Example:

parent = ["x", "a", "b", "c", "d", "e", "f", "g"]
child = ["a", "b", "c"]
//returns true

Example:
When parent has a different order:

parent = ["x", "g", "b", "c", "d", "e", "f", "a"]
child = ["a", "b", "c"]
//It should return false   

How would I achieve this in Javascript?
Edit: I have tried this How to check if an array contains another array? but it did not work for my case

Answer 1

You can run a loop for child and change the index accordingly. You can also use a match variable to detect change in the sequence.

RETURN TRUE

 var parent = ["x", "a", "b", "c", "d", "e", "f", "g"] var child = ["a", "b", "c"]; var initIndex = parent.indexOf(child[0]); var match = true; for(var i=1; i<child.length; i++){ var varIndex = parent.indexOf(child[i]); if( varIndex === initIndex+1){ initIndex = varIndex; continue; } match = false; } console.log(match); 

RETURN FALSE

 var parent = ["x", "g", "b", "c", "d", "e", "f", "a"] var child = ["a", "b", "c"]; var initIndex = parent.indexOf(child[0]); var match = true; for(var i=1; i<child.length; i++){ var varIndex = parent.indexOf(child[i]); if( varIndex === initIndex+1){ initIndex = varIndex; continue; } match = false; } //return false console.log(match); 

USING STRING OPERATION

You can also convert the array to string to avoid those loop:

 var parent = ["x", "g", "b", "c", "d", "e", "f", "a"] var child = ["a", "b", "c"] var parentStr = parent.toString(); var match = parentStr.indexOf(child.toString()) !== -1; //return false console.log(match); parent = ["x", "a", "b", "c", "d", "e", "f", "g"] child = ["a", "b", "c"] parentStr = parent.toString(); match = parentStr.indexOf(child.toString()) !== -1; //return true console.log(match); 

Answer 2

 var parent = ["x", "g", "b", "c", "d", "e", "f", "a"] var child = ["a", "b", "c"] if(parent.join("").search(child.join("")) === -1) { console.log("Not found"); } else { console.log("found") } 

Answer 3

Convert the array to string by using JSON.stringify() and remove the square brackets from child string.

Now check the indexOf child in parent to check if it contains the child.

 let parent = ["x", "a", "b", "c", "d", "e", "f", "g"]; let child = ["a", "b", "c"]; var parStr = JSON.stringify(parent); var chldStr = JSON.stringify(child).replace('[', '').replace(']', '') console.log(parStr.indexOf(chldStr) !== -1); 

Answer 4

You could iterate parent array and use an index for the children array and if the last child is found, return true .

 function check(parent, children) { var index = 0; return parent.some(p => p === children[index] && ++index === children.length); } console.log(check(["x", "a", "b", "c", "d", "e", "f", "g"], ["a", "b", "c"])); console.log(check(["x", "g", "b", "c", "d", "e", "f", "a"], ["a", "b", "c"])); 

A other approach with indexOf

 function check(parent, children) { return children.every((i => c => (i = parent.indexOf(c, i)) !== -1)(0)); } console.log(check(["x", "a", "b", "c", "d", "e", "f", "g"], ["a", "b", "c"])); console.log(check(["x", "g", "b", "c", "d", "e", "f", "a"], ["a", "b", "c"])); 

Answer 5

I have a simple method for small sized arrays of this problem.

1. First join the array to a string, see Array/join
2. Search substring, see String/indexOf

 parent = ["x", "a", "b", "c", "d", "e", "f", "g"]; child = ["a", "b", "c"]; function matchSubArray(parent, child) { parentStr = parent.join(''); childStr = child.join(''); return parentStr.indexOf(childStr) != -1; } matchSubArray(parent, child); 

Answer 6

I wrote a function for this a while back that takes some paramenters:

 Array.prototype.containsArray = function (child, orderSensitivity, caseSensitivity, typeSensitivity) { var self = this; if (orderSensitivity) return orderSensitiveComparer(); else return orderInsensitiveComparer(); function orderSensitiveComparer() { var resultArry = [], placeholder = 0; if (child.length > self.length) return false; for (var i = 0; i < child.length; i++) { for (var k = placeholder; k < self.length; k++) { if (equalityComparer(self[k], child[i])) { resultArry.push(true); if (resultArry.length === child.length) return true; placeholder = k + 1; break; } else resultArry = []; } } return false; } function orderInsensitiveComparer() { for (var i = 0; i < child.length; i++) { var childHasParentElement = false; for (var k = 0; k < self.length; k++) { if (equalityComparer(child[i], self[k])) { childHasParentElement = true; break; } } if (!childHasParentElement) return false; } return true; } function equalityComparer(a, b) { if (caseSensitivity && typeSensitivity) return caseSensitiveEq(a, b) && typeSensitiveEq(a, b); else if (!caseSensitivity && typeSensitivity) return caseInsensitiveEq(a, b) && typeSensitiveEq(a, b); else if (caseSensitivity && !typeSensitivity) return caseSensitiveEq(a, b) && typeInsensitiveEq(a, b); else if (!caseSensitivity && !typeSensitivity) return caseInsensitiveEq(a, b) && typeInsensitiveEq(a, b); else throw "Unknown set of parameters"; function caseSensitiveEq(a, b) { return a == b; } function caseInsensitiveEq(a, b) { return (a + "").toLowerCase() == (b + "").toLowerCase(); } function typeSensitiveEq(a, b) { return typeof(a) === typeof(b); } function typeInsensitiveEq(a, b) { return true; } } } var parent = [1, 2, 3, "a", "b", "c"]; var child = [1, 2, 3]; var child2 = ["1", "2", "3"]; var child3 = ["A", "b", "C"]; var child4 = ["a", "b", "c"]; var child5 = ["c", "b", "a"]; // Tests: console.log(parent.containsArray(parent)); console.log(parent.containsArray(child)); console.log(parent.containsArray(child2)); // parent to child 2, order sensitive, not case, not type. => true. console.log(parent.containsArray(child2, true, false, false)); // parent to child 2, order, not case, type. => false. b/c of type. console.log(parent.containsArray(child2, true, false, true)); // parent to child 3, order, not case, type. => true. console.log(parent.containsArray(child3, true, false, true)); // parent to child 4, order, case and type => true. console.log(parent.containsArray(child4, true, true, true)); // parent to child 4, not order, case and type. => true. console.log(parent.containsArray(child4, false, true, true)); // parent to child 5, not order case or type => true. console.log(parent.containsArray(child5));