JavaScript – How to compare nested arrays

Use JSON.stringify() to compare arrays.

Full example

const set1 = [
    1,
    { data: [1, 2, 3], demo: { arr: [1, 2, 3] } },
    { data: "test" },
];
const set2 = [
    1,
    { data: [1, 2, 3], demo: { arr: [1, 2, 3] } },
    { data: "test" },
];
const set3 = [
    1,
    { data: [1, 2, 3], demo: { arr: [1, 2, 3] } },
    { data: "test1" },
];
const set4 = [
    1,
    { data: [1, 2, 3], demo: { arr: [1, 2, 3, 4] } },
    { data: "test" },
];

const set5 = [1, 2, [1, 2, 3]];
const set6 = [1, 2, [1, 2, 3]];
const set7 = [1, 2, [1, 2, 4]];

function compareArrays(oldData, newData) {
    oldData = JSON.stringify(oldData);
    newData = JSON.stringify(newData);

    if (oldData !== newData) {
        console.log("new data");
    } else {
        console.log("no change");
    }
    console.log("=========================");
}

compareArrays(set1, set1);
compareArrays(set1, set2);
compareArrays(set1, set3);
compareArrays(set1, set4);
compareArrays(set3, set4);
compareArrays(set4, set4);
compareArrays(set5, set6);
compareArrays(set6, set7);

Output

no change
=========================
no change
=========================
new data
=========================
new data
=========================
new data
=========================
no change
=========================
no change
=========================
new data
=========================

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