Function applyOverride

06.Router/basic/js/vue-router.js:1730–1791

(Vue)

  };

  function applyOverride (Vue) {
    var _Vue$util = Vue.util;
    var extend = _Vue$util.extend;
    var isArray = _Vue$util.isArray;
    var defineReactive = _Vue$util.defineReactive;

    // override Vue's init and destroy process to keep track of router instances
    var init = Vue.prototype._init;
    Vue.prototype._init = function (options) {
      options = options || {};
      var root = options._parent || options.parent || this;
      var router = root.$router;
      var route = root.$route;
      if (router) {
        // expose router
        this.$router = router;
        router._children.push(this);
        /* istanbul ignore if */
        if (this._defineMeta) {
          // 0.12
          this._defineMeta('$route', route);
        } else {
          // 1.0
          defineReactive(this, '$route', route);
        }
      }
      init.call(this, options);
    };

    var destroy = Vue.prototype._destroy;
    Vue.prototype._destroy = function () {
      if (!this._isBeingDestroyed && this.$router) {
        this.$router._children.$remove(this);
      }
      destroy.apply(this, arguments);
    };

    // 1.0 only: enable route mixins
    var strats = Vue.config.optionMergeStrategies;
    var hooksToMergeRE = /^(data|activate|deactivate)$/;

    if (strats) {
      strats.route = function (parentVal, childVal) {
        if (!childVal) return parentVal;
        if (!parentVal) return childVal;
        var ret = {};
        extend(ret, parentVal);
        for (var key in childVal) {
          var a = ret[key];
          var b = childVal[key];
          // for data, activate and deactivate, we need to merge them into
          // arrays similar to lifecycle hooks.
          if (a && hooksToMergeRE.test(key)) {
            ret[key] = (isArray(a) ? a : [a]).concat(b);
          } else {
            ret[key] = b;
          }
        }