Any difference between x || [] and x ?? [] in javascript?

Question

I've see both x || [] and x ?? [] used for providing a fallback value if x is nullish. Are there any cases where these two give different results?

Answer 1

If x was a non-nullish falsey value, it would be different.

x = 0;
x = x ?? []
console.log(x);



y = null;
y = y ?? []
console.log(y);

Answer 2

These expressions x || [] and x ?? [] are logical assignments in Javascript.

x ?? [] is used to represent null or undefined cases while x || [] represent true if either a or b is true.

• x ?? [] works by evaluating if the left side of the expression is null or undefined.

• x || [] works by evaluating if a or b is true. If a is true continue in the if statement. If b is true, continue in the if statement.