Improving speed of List.search

[sheffieldnikki]

For large numbers of items and/or slower CPUs the speed of searching can become noticeable. This drop-in replacement optimises the standard search function in list.js/src/search.js:

var search = {
    list: function() { ... }

with:

var search = {
    list: function() {
      for (var k = 0, kl = list.items.length; k < kl; k++) {
        var item = list.items[k];
        item.found = false;
        if (searchString === "") continue;
        var values = item.values();
        for (var j = 0, jl = columns.length; j < jl; j++) {
          var column = columns[j];
          if (values.hasOwnProperty(column) && values[column] !== undefined && values[column] !== null) {
            var text = (typeof values[column] !== 'string') ? values[column].toString() : values[column];
            if (text.toLowerCase().indexOf(searchString) !== -1) {
              item.found = true;
              break;
            }
          }
        }
      }
    }

Search is 63% faster in Chrome v80 and 30% faster in Firefox v74. The 2 biggest wins are replacing text.search(searchString) (for regular expressions, but List.js only supports searching on a string) with text.indexOf(searchString), and only calling .toString() in the inner loop if needed.

Here is a JSPerf comparing 3 different case-insensitive string matching functions.

[sheffieldnikki]

You can also use this faster search without needing to modify the List.js library: just pass it as a custom search argument: see #678

listObj.search('Jonny', searchFunction); // Custom search for Jonny
listObj.search('Jonny', ['name'], searchFunction); // Custom search in the 'name' column

function searchFunction(searchString, columns) {
  for (var k = 0, kl = listObj.items.length; k < kl; k++) {
    var item = listObj.items[k];
    item.found = false;
    if (searchString === "") continue;
    var values = item.values();
    for (var j = 0, jl = columns.length; j < jl; j++) {
      var column = columns[j];
      if (values.hasOwnProperty(column) && values[column] !== undefined && values[column] !== null) {
        var text = (typeof values[column] !== 'string') ? values[column].toString() : values[column];
        if (text.toLowerCase().indexOf(searchString) !== -1) {
          item.found = true;
          break;
        }
      }
   }
};

[sheffieldnikki]

Now updated to move item.values() call out of inner loop, thanks to @buczek

[javve]

This is awesome and now a part of #696 ❤️

[javve]

It'll be release as part of v2.2.0