bind-late/index.js

Late binding of overridable object properties.

"use strict";

var assign = require("object-assign");
var isPlainObject = require("is-plain-object");
var lazy = require("lazy-object").defineLazyProperty;
var makeOverridable = require("make-overridable");

var keys = function (object, f) {
  Object.keys(object).forEach(f);
  return object;
};

var traverse = function (object, f) {
  var root = arguments[2] === undefined ? object : arguments[2];
  return (function () {
    return keys(object, function (key) {
      var value = object[key];

      if (isPlainObject(value)) {
        traverse(value, f, root);
      } else {
        f(value, key, object);
      }
    });
  })();
};

var isUnderscored = function (f) {
  return f.toString().substr(0, 12) === "function (_)";
};
var isLateBinding = function (x) {
  return x instanceof Function && isUnderscored(x);
};
function Dumb(object) {
  assign(this, object);
}

var doBindLate = function (object) {
  return traverse(object, function (value, key, node) {
    if (isLateBinding(value)) {
      lazy(node, key, function () {
        return value(object);
      });
    }
  });
};

var bindLate = function (object) {
  return doBindLate(new Dumb(object));
};

module.exports = makeOverridable(bindLate);
module.exports.bindLate = bindLate;