js-search/source/IndexStrategy/AllSubstringsIndexStrategy.js

JS Search is an efficient, client-side search library for JavaScript and JSON objects

// @flow

import type { IIndexStrategy } from './IndexStrategy';

/**
 * Indexes for all substring searches (e.g. the term "cat" is indexed as "c", "ca", "cat", "a", "at", and "t").
 */
export class AllSubstringsIndexStrategy implements IIndexStrategy {

  /**
   * @inheritDocs
   */
  expandToken(token : string) : Array<string> {
    var expandedTokens = [];
    var string;

    for (var i = 0, length = token.length; i < length; ++i) {
      string = '';

      for (var j = i; j < length; ++j) {
        string += token.charAt(j);
        expandedTokens.push(string);
      }
    }

    return expandedTokens;
  }
};