How to sort an array of objects correctly by an object's alphanumeric name value?-CodePudding

I am trying to sort an array of objects by the name field but the ordering is wrong.

The order I am getting is [1, 10, 11, 2, 20, 21, 3]

Instead of [1, 2, 3, .... 10, 11, 20, 21]

It is sorting but putting 10 ahead of 2

Here is the code I am currently using.

const arr = [
    
    {
        "name": "Action 10",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 11",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 2",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 20",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 21",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 3",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 4",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 5",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 6",
        "color": "transparent",
        "type": "components"
    },
    {
        "name": "Action 1",
        "color": "transparent",
        "type": "components"
    }
]

function sorter(a, b) {
    if (a.name < b.name) return -1;
    if (a.name > b.name) return 1;
    return 0;
}

console.log(arr.sort(sorter));

CodePudding user response：

One could give the numeric sorting option of String.prototype.localeCompare a try ...

const arr = [{
  name: "Action 10", color: "transparent", type: "components"
}, {
  name: "Action 11", color: "transparent", type: "components"
}, {
  name: "Action 2", color: "transparent", type: "components"
}, {
  name: "Action 20", color: "transparent", type: "components"
}, {
  name: "Action 21", color: "transparent", type: "components"
}, {
  name: "Action 3", color: "transparent", type: "components"
}, {
  name: "Action 4", color: "transparent", type: "components"
}, {
  name: "Action 5", color: "transparent", type: "components"
}, {
  name: "Action 6", color: "transparent", type: "components"
}, {
  name: "Action 1", color: "transparent", type: "components"
}];

function sorter(a, b) {
  return a.name.localeCompare(b.name, undefined, { numeric: true });
}
console.log(arr.sort(sorter));

.as-console-wrapper { min-height: 100%!important; top: 0; }

CodePudding user response：

The ordering is correct. The string "Action 10" collates greater than Action 1 and less than Action 2, because string comparison is done on a character by character basis.

The algorithm for string comparision is found here: https://262.ecma-international.org/5.1/#sec-11.8.5

[If] both px and py are Strings

If py is a prefix of px, return false. (A String value p is a prefix of String value q if q can be the result of concatenating p and some other String r. Note that any String is a prefix of itself, because r may be the empty String.)

If px is a prefix of py, return true.

Let k be the smallest nonnegative integer such that the character at position k within px is different from the character at position k within py. (There must be such a k, for neither String is a prefix of the other.)

Let m be the integer that is the code unit value for the character at position k within px.

Let n be the integer that is the code unit value for the character at position k within py.

If m < n, return true. Otherwise, return false.

Or, as a javascript function, the expression str1 < str2 is evaluated as if this function were invoked (not that anybody sane would implement the algorithm as described in the spec):

function lt( px, py ) {
    const prefixOf = (x,y) => x.slice(0,y.length) === y;

    if ( prefixOf(px,py) ) return false;
    if ( prefixOf(py,px) ) return true;

    let k = 0 ;
    while ( px[k] === py[k] ) {
          k;
    }
 
    m = px.charCodeAt(k);
    n = py.charCodeAt(k);

    return m < n ? true : false;
  }

If you want to order things according to the semantic meaning of name, you'll need to partition the string into a list of its non-numeric and numeric segments, convert the numeric bits into numbers, and then compare the segments in order from left to right.

CodePudding user response：

You can use regular expressions:

const sorter = (a, b) =>  a.name.match(/\d /) -  b.name.match(/\d /);

DEMO

const arr = [{"name": "Action 10","color": "transparent","type": "components"}, {"name": "Action 11","color": "transparent","type": "components"}, {"name": "Action 2","color": "transparent","type": "components"}, {"name": "Action 20","color": "transparent","type": "components"}, {"name": "Action 21","color": "transparent","type": "components"}, {"name": "Action 3","color": "transparent","type": "components"}, {"name": "Action 4","color": "transparent","type": "components"}, {"name": "Action 5","color": "transparent","type": "components"}, {"name": "Action 6","color": "transparent","type": "components"}, {"name": "Action 1","color": "transparent","type": "components"}]

function sorter(a, b) {
    return  a.name.match(/\d /)[0] -  b.name.match(/\d /)[0];
}

console.log(arr.sort(sorter));