sort-keys

Require object keys to be sorted

When declaring multiple properties, some developers prefer to sort property names alphabetically to more easily find and/or diff necessary properties at a later time. Others feel that it adds complexity and becomes burden to maintain.

Rule Details

This rule checks all property definitions of object expressions and verifies that all variables are sorted alphabetically.

Examples of incorrect code for this rule:

/*eslint sort-keys: "error"*/

let obj1 = {a: 1, c: 3, b: 2};
let obj2 = {a: 1, "c": 3, b: 2};

// Case-sensitive by default.
let obj3 = {a: 1, b: 2, C: 3};

// Non-natural order by default.
let obj4 = {1: a, 2: c, 10: b};

// This rule checks computed properties which have a simple name as well.
// Simple names are names which are expressed by an Identifier node or a Literal node.
const S = Symbol("s")
let obj5 = {a: 1, ["c"]: 3, b: 2};
let obj6 = {a: 1, [S]: 3, b: 2};
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Examples of correct code for this rule:

/*eslint sort-keys: "error"*/

let obj1 = {a: 1, b: 2, c: 3};
let obj2 = {a: 1, "b": 2, c: 3};

// Case-sensitive by default.
let obj3 = {C: 3, a: 1, b: 2};

// Non-natural order by default.
let obj4 = {1: a, 10: b, 2: c};

// This rule checks computed properties which have a simple name as well.
let obj5 = {a: 1, ["b"]: 2, c: 3};
let obj6 = {a: 1, [b]: 2, c: 3};

// This rule ignores computed properties which have a non-simple name.
let obj7 = {a: 1, [c + d]: 3, b: 2};
let obj8 = {a: 1, ["c" + "d"]: 3, b: 2};
let obj9 = {a: 1, [`${c}`]: 3, b: 2};
let obj10 = {a: 1, [tag`c`]: 3, b: 2};

// This rule does not report unsorted properties that are separated by a spread property.
let obj11 = {b: 1, ...c, a: 2};
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Options

{
    "sort-keys": ["error", "asc", {"caseSensitive": true, "natural": false, "minKeys": 2}]
}
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The 1st option is "asc" or "desc".

• "asc" (default) - enforce properties to be in ascending order.
• "desc" - enforce properties to be in descending order.

The 2nd option is an object which has the following properties.

• caseSensitive - if true, enforce properties to be in case-sensitive order. Default is true.
• minKeys - Specifies the minimum number of keys that an object should have in order for the object’s unsorted keys to produce an error. Default is 2, which means by default all objects with unsorted keys will result in lint errors.
• natural - if true, enforce properties to be in natural order. Default is false. Natural Order compares strings containing combination of letters and numbers in the way a human being would sort. It basically sorts numerically, instead of sorting alphabetically. So the number 10 comes after the number 3 in Natural Sorting.
• allowLineSeparatedGroups - if true, the rule allows to group object keys through line breaks. In other words, a blank line after a property will reset the sorting of keys. Default is false.

Example for a list:

With natural as true, the ordering would be 1 3 6 8 10

With natural as false, the ordering would be 1 10 3 6 8

desc

Examples of incorrect code for the "desc" option:

/*eslint sort-keys: ["error", "desc"]*/

let obj1 = {b: 2, c: 3, a: 1};
let obj2 = {"b": 2, c: 3, a: 1};

// Case-sensitive by default.
let obj3 = {C: 1, b: 3, a: 2};

// Non-natural order by default.
let obj4 = {10: b, 2: c, 1: a};
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Examples of correct code for the "desc" option:

/*eslint sort-keys: ["error", "desc"]*/

let obj1 = {c: 3, b: 2, a: 1};
let obj2 = {c: 3, "b": 2, a: 1};

// Case-sensitive by default.
let obj3 = {b: 3, a: 2, C: 1};

// Non-natural order by default.
let obj4 = {2: c, 10: b, 1: a};
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insensitive

Examples of incorrect code for the {caseSensitive: false} option:

/*eslint sort-keys: ["error", "asc", {caseSensitive: false}]*/

let obj1 = {a: 1, c: 3, C: 4, b: 2};
let obj2 = {a: 1, C: 3, c: 4, b: 2};
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Examples of correct code for the {caseSensitive: false} option:

/*eslint sort-keys: ["error", "asc", {caseSensitive: false}]*/

let obj1 = {a: 1, b: 2, c: 3, C: 4};
let obj2 = {a: 1, b: 2, C: 3, c: 4};
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natural

Examples of incorrect code for the {natural: true} option:

/*eslint sort-keys: ["error", "asc", {natural: true}]*/

let obj = {1: a, 10: c, 2: b};
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Examples of correct code for the {natural: true} option:

/*eslint sort-keys: ["error", "asc", {natural: true}]*/

let obj = {1: a, 2: b, 10: c};
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minKeys

Examples of incorrect code for the {minKeys: 4} option:

/*eslint sort-keys: ["error", "asc", {minKeys: 4}]*/

// 4 keys
let obj1 = {
    b: 2,
    a: 1, // not sorted correctly (should be 1st key)
    c: 3,
    d: 4,
};

// 5 keys
let obj2 = {
    2: 'a',
    1: 'b', // not sorted correctly (should be 1st key)
    3: 'c',
    4: 'd',
    5: 'e',
};
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Examples of correct code for the {minKeys: 4} option:

/*eslint sort-keys: ["error", "asc", {minKeys: 4}]*/

// 3 keys
let obj1 = {
    b: 2,
    a: 1,
    c: 3,
};

// 2 keys
let obj2 = {
    2: 'b',
    1: 'a',
};
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allowLineSeparatedGroups

Examples of incorrect code for the {allowLineSeparatedGroups: true} option:

/*eslint sort-keys: ["error", "asc", {allowLineSeparatedGroups: true}]*/

let obj1 = {
    b: 1,
    c () {

    },
    a: 3
}

let obj2 = {
    b: 1,
    c: 2,

    z () {

    },
    y: 3
}

let obj3 = {
    b: 1,
    c: 2,

    z () {

    },
    // comment
    y: 3,
}

let obj4 = {
    b: 1
    // comment before comma
    , a: 2
};
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Examples of correct code for the {allowLineSeparatedGroups: true} option:

/*eslint sort-keys: ["error", "asc", {allowLineSeparatedGroups: true}]*/

let obj1 = {
    e: 1,
    f: 2,
    g: 3,

    a: 4,
    b: 5,
    c: 6
}

let obj2 = {
    b: 1,

    // comment
    a: 4,
    c: 5,
}

let obj3 = {
    c: 1,
    d: 2,

    b () {

    },
    e: 3,
}

let obj4 = {
    c: 1,
    d: 2,
    // comment

    // comment
    b() {

    },
    e: 4
}

let obj5 = {
    b,

    [foo + bar]: 1,
    a
}

let obj6 = {
    b: 1
    // comment before comma

    ,
    a: 2
};

var obj7 = {
    b: 1,

    a: 2,
    ...z,
    c: 3
}
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When Not To Use It

If you don’t want to notify about properties’ order, then it’s safe to disable this rule.

Compatibility

• JSCS: validateOrderInObjectKeys

Related Rules

• sort-imports
• sort-vars

Version

This rule was introduced in ESLint v3.3.0.

Resources

• Rule source
• Tests source