Setting Application Contexts (AppCons)

Using AppCons in your Application

To use AppCons in your application, you must first import the TAO into the file that will signal a change in Application Context:

import TAO from '@tao.js/core';

OR

const TAO = require('@tao.js/core');

Setting Context

Signal a change in Application Context by using the setCtx method on the TAO:

TAO.setCtx({ t: 'App', a: 'Enter', o: 'Portal' });
// OR
TAO.setCtx({ term: 'App', action: 'Enter', orient: 'Portal' });

Include Data when Setting Context

You can also pass along data as the 2nd argument to the setCtx method on the TAO.

Data can be included in several different forms.

1. as an Object with properties of the same names as the trigram

TAO.setCtx({ t: 'App', a: 'Enter', o: 'Portal' }, {
  App: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  Enter: { … },
  Portal: { … },
});

Special Note: not all properties from the trigram are required, the inclusion of Enter and Portal are illustrative here

2. as an Object with properties named t or term, a or action, and/or o or orient:

TAO.setCtx({ t: 'App', a: 'Enter', o: 'Portal' }, {
  t: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  a: { … },
  o: { … },
});
// OR
TAO.setCtx({ term: 'App', action: 'Enter', orient: 'Portal' }, {
  term: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  action: { … },
  orient: { … },
});

This form can be useful when the setting of the context is more dynamic and the keys aren't necessarily known ahead of time. Additionally, the forms can be mixed if you want.

Special Note: no matter how the data is passed in, when we look at handlers the data sent to the handler will always be consistent in the form from the first option as properties using the names identified by the trigram

3. as an Array ordered as [term, action, orient]

TAO.setCtx({ t: 'App', a: 'Enter', o: 'Portal' }, [
  {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  { … },
  { … },
]);

Special Note: not all properties from the trigram are required, the inclusion of all 3 entries is illustrative here

Create an AppCon and set Context

The @tao.js/core package also exports a class called AppCon that allows you to instantiate instances of AppCons to then pass to the TAO using setAppCtx.

First, ensure you are importing it where you plan to use it:

import TAO, { AppCon } from '@tao.js/core';

OR

const TAO, { AppCon } = require('@tao.js/core');

Next instantiate an AppCon and set it using setAppCtx:

const appEnterPortal = new AppCon('App', 'Enter', 'Portal');
…
TAO.setAppCtx(appEnterPortal);

Create an AppCon with data and set Context

Instantiating AppCons with data is very similar to passing data directly to the TAO's setCtx method by using the arguments after the first 3 args.

Like setCtx, the AppCon constructor offers several options.

1. as a single Object with properties of the same names as the trigram

const appEnterPortal = new AppCon('App', 'Enter', 'Portal', {
  App: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  Enter: { … },
  Portal: { … },
});
…
TAO.setAppCtx(appEnterPortal);

2. as a single Object with properties named t or term, a or action, and/or o or orient

const appEnterPortal = new AppCon('App', 'Enter', 'Portal', {
  t: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  a: { … },
  o: { … },
});
// OR
const appEnterPortal = new AppCon('App', 'Enter', 'Portal', {
  term: {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  action: { … },
  orient: { … },
});
…
TAO.setAppCtx(appEnterPortal);

3. as an Array ordered as [term, action, orient]

const appEnterPortal = new AppCon('App', 'Enter', 'Portal', [
  {
    title: 'Patois - words for the way you talk',
    url: 'https://pato.is'
  },
  { … },
  { … },
]);
…
TAO.setAppCtx(appEnterPortal);

Special Note: not all properties from the trigram are required, the inclusion of all 3 entries is illustrative here

4. as a set of up to 3 args in series ordered as term, action, orient

const appEnterPortal = new AppCon('App', 'Enter', 'Portal', { title: 'Patois - …' }, new Date(), { … });
…
TAO.setAppCtx(appEnterPortal);

This Example illustrates that data can be set for an AppCon that is not necessarily itself an Object in the case of setting the Enter Action data to a Date value, and this is possible for any of the other forms of setting data above, not just this form.

AppCon instantiation has more to offer

You can also export AppCons to be imported and used elswehwere in your app.

AppCon instantiation will also come in to play when we look at Chaining AppCons.

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