max-lines.md

enforce a maximum file length (max-lines)

Some people consider large files a code smell. Large files tend to do a lot of things and can make it hard following what's going. While there is not an objective maximum number of lines considered acceptable in a file, most people would agree it should not be in the thousands. Recommendations usually range from 100 to 500 lines.

Rule Details

This rule enforces a maximum number of lines per file, in order to aid in maintainability and reduce complexity.

Options

This rule has a number or object option:

• "max" (default 300) enforces a maximum number of lines in a file

• "skipBlankLines": true ignore lines made up purely of whitespace.

• "skipComments": true ignore lines containing just comments

code

Examples of incorrect code for this rule with a max value of 2:

/*eslint max-lines: ["error", 2]*/
var a,
    b,
    c;

/*eslint max-lines: ["error", 2]*/

var a,
    b,c;

/*eslint max-lines: ["error", 2]*/
// a comment
var a,
    b,c;

Examples of correct code for this rule with a max value of 2:

/*eslint max-lines: ["error", 2]*/
var a,
    b, c;

/*eslint max-lines: ["error", 2]*/

var a, b, c;

/*eslint max-lines: ["error", 2]*/
// a comment
var a, b, c;

skipBlankLines

Examples of incorrect code for this rule with the { "skipBlankLines": true } option:

/*eslint max-lines: ["error", 2, {"skipBlankLines": true}]*/

var a,
    b,
    c;

Examples of correct code for this rule with the { "skipBlankLines": true } option:

/*eslint max-lines: ["error", 2, {"skipBlankLines": true}]*/

var a,
    b, c;

skipComments

Examples of incorrect code for this rule with the { "skipComments": true } option:

/*eslint max-lines: ["error", 2, {"skipComments": true}]*/
// a comment
var a,
    b,
    c;

Examples of correct code for this rule with the { "skipComments": true } option:

/*eslint max-lines: ["error", 2, {"skipComments": true}]*/
// a comment
var a,
    b, c;

When Not To Use It

You can turn this rule off if you are not concerned with the number of lines in your files.

Further reading

• Software Module size and file size

Related Rules

• complexity
• max-depth
• max-nested-callbacks
• max-params
• max-statements

Compatibility

• JSCS: maximumNumberOfLines