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Enforce or disallow newlines between operands of ternary expressions (multiline-ternary)

JavaScript allows operands of ternary expressions to be separated by newlines, which can improve the readability of your program.

For example:

var foo = bar > baz ? value1 : value2;

The above can be rewritten as the following to improve readability and more clearly delineate the operands:

var foo = bar > baz ?
    value1 :
    value2;

Rule Details

This rule enforces or disallows newlines between operands of a ternary expression. Note: The location of the operators is not enforced by this rule. Please see the operator-linebreak rule if you are interested in enforcing the location of the operators themselves.

Options

This rule has a string option:

  • "always" (default) enforces newlines between the operands of a ternary expression.
  • "always-multiline" enforces newlines between the operands of a ternary expression if the expression spans multiple lines.
  • "never" disallows newlines between the operands of a ternary expression.

always

This is the default option.

Examples of incorrect code for this rule with the "always" option:

/*eslint multiline-ternary: ["error", "always"]*/

foo > bar ? value1 : value2;

foo > bar ? value :
    value2;

foo > bar ?
    value : value2;

Examples of correct code for this rule with the "always" option:

/*eslint multiline-ternary: ["error", "always"]*/

foo > bar ?
    value1 :
    value2;

foo > bar ?
    (baz > qux ?
        value1 :
        value2) :
    value3;

always-multiline

Examples of incorrect code for this rule with the "always-multiline" option:

/*eslint multiline-ternary: ["error", "always-multiline"]*/

foo > bar ? value1 :
    value2;

foo > bar ?
    value1 : value2;

foo > bar &&
    bar > baz ? value1 : value2;

Examples of correct code for this rule with the "always-multiline" option:

/*eslint multiline-ternary: ["error", "always-multiline"]*/

foo > bar ? value1 : value2;

foo > bar ?
    value1 :
    value2;

foo > bar ?
    (baz > qux ? value1 : value2) :
    value3;

foo > bar ?
    (baz > qux ?
        value1 :
        value2) :
    value3;

foo > bar &&
    bar > baz ?
        value1 :
        value2;

never

Examples of incorrect code for this rule with the "never" option:

/*eslint multiline-ternary: ["error", "never"]*/

foo > bar ? value :
    value2;

foo > bar ?
    value : value2;

foo >
    bar ?
    value1 :
    value2;

Examples of correct code for this rule with the "never" option:

/*eslint multiline-ternary: ["error", "never"]*/

foo > bar ? value1 : value2;

foo > bar ? (baz > qux ? value1 : value2) : value3;

foo > bar ? (
    baz > qux ? value1 : value2
) : value3;

When Not To Use It

You can safely disable this rule if you do not have any strict conventions about whether the operands of a ternary expression should be separated by newlines.

Compatibility

Version

This rule was introduced in ESLint 3.1.0.

Resources

© JS Foundation and other contributors
Licensed under the MIT License.
https://eslint.org/docs/rules/multiline-ternary