Disallow Floating Decimals (no-floating-decimal)

Float values in JavaScript contain a decimal point, and there is no requirement that the decimal point be preceded or followed by a number. For example, the following are all valid JavaScript numbers:

var num = .5;
var num = 2.;
var num = -.7;

Although not a syntax error, this format for numbers can make it difficult to distinguish between true decimal numbers and the dot operator. For this reason, some recommend that you should always include a number before and after a decimal point to make it clear the intent is to create a decimal number.

Rule Details

This rule is aimed at eliminating floating decimal points and will warn whenever a numeric value has a decimal point but is missing a number either before or after it.

The following patterns are considered warnings:

var num = .5;
var num = 2.;
var num = -.7;

The following patterns are not considered warnings:

var num = 0.5;
var num = 2.0;


When Not To Use It

If you aren’t concerned about misinterpreting floating decimal point values, then you can safely turn this rule off.

Further Reading


This rule was introduced in ESLint 0.0.6.