JavaScript Arrays Array comparison
Example
For simple array comparison you can use JSON stringify and compare the output strings:
JSON.stringify(array1) === JSON.stringify(array2)
Note: that this will only work if both objects are JSON serializable and do not contain cyclic references. It may throw
TypeError: Converting circular structure to JSON
You can use a recursive function to compare arrays.
function compareArrays(array1, array2) {
var i, isA1, isA2;
isA1 = Array.isArray(array1);
isA2 = Array.isArray(array2);
if (isA1 !== isA2) { // is one an array and the other not?
return false; // yes then can not be the same
}
if (! (isA1 && isA2)) { // Are both not arrays
return array1 === array2; // return strict equality
}
if (array1.length !== array2.length) { // if lengths differ then can not be the same
return false;
}
// iterate arrays and compare them
for (i = 0; i < array1.length; i += 1) {
if (!compareArrays(array1[i], array2[i])) { // Do items compare recursively
return false;
}
}
return true; // must be equal
}
WARNING:
Using the above function is dangerous and should be wrapped in a try catch if you suspect there is a chance the array has cyclic references (a reference to an array that contains a reference to itself)
a = [0] ;
a[1] = a;
b = [0, a];
compareArrays(a, b); // throws RangeError: Maximum call stack size exceeded
Note: The function uses the strict equality operator
===to compare non array items{a: 0} === {a: 0}isfalse
