Invalid assignment left-hand side, javascript

Answer 1

+= means "take the thing on the left, add this to it, and store the result in the thing on the left". The left-hand side of your += is a literal (the first one is '

). You can't assign to literals.

Put it another way, a += b basically means a = a + b. You can see how that doesn't work if a is a literal rather than a variable.

You just want + there:

var addhtml = '
'
+ '
e["screen_name]
'
+ '
'
+ '
e["description"]
'
+ '
';
console.log(addhtml);

To give you an idea of the difference between + and +=:

var a, b;
a = "foo";
b = a + "bar";  // Doesn't modify `a`
console.log(a); // "foo"
console.log(b); // "foobar"

vs.

var a, b;
a = "foo";
b = a += "bar"; // Modifies `a` (assigning the result to `b` is unusual -- very -- but valid)
console.log(a); // "foobar" - note it's changed
console.log(b); // "foobar"

---

Off-topic:

I'd also recommend indenting the subsequent lines of the assignment statement, but that's just style:

var addhtml = '
'
    + '
e["screen_name]
'
    + '
'
    + '
e["description"]
'
    + '
';
console.log(addhtml);

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