This JavaScript exception missing = in const declaration occurs if a const is declared and value is not provided(like const ABC_DEF;). Need to provide the value in same statement (const ABC_DEF = ‘#ee0’).
Message:
SyntaxError: Const must be initialized (Edge)
SyntaxError: missing = in const declaration (Firefox)
SyntaxError: Missing initializer in const declaration (Chrome)
Error Type:
SyntaxError
Cause of Error: A constant value cannot be changed by the program while execution. It cannot be altered through re-assignment also.
Example 1: In this example, a const is declared but not initialized so the error has occurred.
HTML
<!DOCTYPE html>
<html>
<head>
<title>Syntax Error</title>
</head>
<body>
<script>
const GFG;
document.write(GFG);
</script>
</body>
</html>
|
Output:
SyntaxError: Const must be initialized
Example 2: In this example, a const is declared and initialized later, so the error has occurred.
HTML
<!DOCTYPE html>
<html>
<head>
<title>Syntax Error</title>
</head>
<body>
<script>
const INIT_VAL;
// invalid statement
INIT_VAL = 5;
document.write(INIT_VAL);
</script>
</body>
</html>
|
Output:
SyntaxError: Const must be initialized