Simple Method Calls

Meteor makes making real-time web apps extremely easy. But calling a Meteor method and showing the result can be a little tricky. It usually involves using the reactive-var package and calling the method somewhere else. It's just not so meteoric.

The following example shows a how to call an add method with a few numbers and return the result with a template helper.

// showing meteor method result
// using reactive-var package

Template.hello.created = function () {
  this.total = new ReactiveVar();
};

Template.hello.rendered = function () {
  var self = this;
  Meteor.call('add', 4, 5, function (err, res) {
    self.total.set(res);
  });
};

// {{total}} can be used inside hello template
Template.hello.helpers({
  total: function () {
    var tpl = Template.instance();
    return tpl.total.get();
  }
});

// server-side code
Meteor.methods({
  add: function (x, y) {
    return x + y;
  }
});

The code can become a real mess and simply it's just too much code for doing something like this.

Simple Example

Using this (mnmtanish:call) package the above example can be written like this.

// {{total}} can be used inside hello template
Template.hello.helpers({
  total: function () {
    var uniqueId = 'add-numbers';
    return Call(uniqueId, 'add', 4, 5).result();
  }
});

A method call id is used to cache method call results. The method will be called only once for a particular id. If you want to call the method again, use a different id or use the call.update() method explained below.

Another Example

This is another example which also uses 2 helper arguments, checks whether the result is ready and handles method errors.

Template.hello.helpers({
  total: function (x, y) {
    var id = 'add-'+x+'-'+y;
    var call = Call(id, 'add', x, y);

    if(!call.ready()) {
      // method call has not finished yet
      return 'adding numbers...';
    }

    var err = call.error();
    if(err) {
      // method call returned an error
      console.error(err);
      return 'error';
    }

    return call.result();
  }
});

Installation

Add this package with this command.

meteor add mnmtanish:call

API

Call(uniqueId, methodName, arg1, arg2, ...)

Calls a meteor method and returns a MethodCall instance (let's call it a call). It can be returned from a helper directly it's methods can be used. If the uniqueId already exists its result (MethodCall instance) will be returned without calling the method again.

Call.get(id)

Returns a MethodCall instance by its unique id.

call.ready()

Reactive. Returns whether the method call has finished or is still being processed on the server;

call.error()

Reactive. Returns a method error if the method call ends with an error.

call.result()

Reactive. Returns method result if the method call ends successfully.

call.update()

Call the method again.

call.destroy()

Deletes the method call and result from cache.

thani-sh/meteor-call