mathjs/lib/function/construction/select.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.

module.exports = function (math) {
  /**
   * Wrap any value in a Selector, allowing to perform chained operations on
   * the value.
   *
   * All methods available in the math.js library can be called upon the selector,
   * and then will be evaluated with the value itself as first argument.
   * The selector can be closed by executing selector.done(), which will return
   * the final value.
   *
   * Example usage:
   *     math.select(3)
   *         .add(4)
   *         .subtract(2)
   *         .done();     // 5
   *     math.select( [[1, 2], [3, 4]] )
   *         .set([1, 1], 8)
   *         .multiply(3)
   *         .done();     // [[24, 6], [9, 12]]
   *
   * The Selector has a number of special functions:
   * - done()     Finalize the chained operation and return the selectors value.
   * - valueOf()  The same as done()
   * - toString() Executes math.format() onto the selectors value, returning
   *              a string representation of the value.
   * - get(...)   Get a subselection of the selectors value. Only applicable when
   *              the value has a method get, for example when value is a Matrix
   *              or Array.
   * - set(...)   Replace a subselection of the selectors value. Only applicable
   *              when the value has a method get, for example when value is a
   *              Matrix or Array.
   *
   * @param {*} value
   * @return {math.chaining.Selector} selector
   */
  math.select = function select(value) {
    // TODO: check number of arguments
    return new math.chaining.Selector(value);
  };
};