SyntaxError: identifier starts immediately after numeric literal
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The JavaScript exception "identifier starts immediately after numeric literal" occurs when an identifier started with a digit. Identifiers can only start with a letter, underscore (_), or dollar sign ($).
Message#
SyntaxError: Invalid or unexpected token (V8-based)
SyntaxError: identifier starts immediately after numeric literal (Firefox)
SyntaxError: No identifiers allowed directly after numeric literal (Safari)
Error type#
{{jsxref("SyntaxError")}}
What went wrong?#
The names of variables, called identifiers, conform to certain rules, which your code must adhere to!
A JavaScript identifier must start with a letter, underscore (_), or dollar sign ($). They can't start with a digit! Only subsequent characters can be digits (0-9).
Examples#
Variable names starting with numeric literals#
Variable names can't start with numbers in JavaScript. The following fails:
```js-nolint example-bad const 1life = "foo"; // SyntaxError: identifier starts immediately after numeric literal
const foo = 1life; // SyntaxError: identifier starts immediately after numeric literal
You will need to rename your variable to avoid the leading number.
```js example-good
const life1 = "foo";
const foo = life1;
In JavaScript, there is a syntactic peculiarity when calling properties or methods on numbers. If you want to call a method on an integer, you cannot immediately use a dot after the number because the dot is interpreted as the start of a decimal fraction, causing the parser to see the method's name as an identifier immediately after a number literal. To avoid this, you need to either wrap the number in parentheses or use a double dot, where the first dot is a decimal point for the number literal and the second dot is the property accessor.
```js-nolint example-bad alert(typeof 1.toString()) // SyntaxError: identifier starts immediately after numeric literal
Correct ways to call methods on numbers:
```js-nolint example-good
// Wrap the number in parentheses
alert(typeof (1).toString());
// Add an extra dot for the number literal
alert(typeof 2..toString());
// Use square brackets
alert(typeof 3["toString"]());