@dws/muster-repl

Introduction

A REPL for the Muster library.

Installation

npm install -g @dws/muster-repl@next

Usage

To start the Muster REPL simply run:

muster-repl

Muster REPL supports following commands:

• <graph_node> - evaluate a graph node
• subscribe <graph_node> - subscribe to a graph node
• sub <graph_node> - alias for the subscribe
• subscribe:<name> <graph_node> - subscribe to a graph node and name the subscription
• unsubscribe <name> - remove a named subscription
• unsub <name> - alias for the unsubscribe
• subscriptions - list all open subscriptions and their values
• subs - alias for the subscriptions
• load <file_path> - load an external muster graph

Example REPL queries

Muster version: 5.0.0-rc.6
Muster REPL version: 5.0.0-rc.6

> value('Hello, world')
'value({value: "Hello, world"})'
> computed([value('world')], (name) => `Hello, ${name}`)
'value({value: "Hello, world"})'
> muster({ name: 'Bob' })
'Created a new muster instance.'
> ref('name')
'value({value: "Bob"})'

Open and close subscriptions

Muster version: 5.0.0-rc.6
Muster REPL version: 5.0.0-rc.6

> muster({ name: variable('Bob') })
'Created a new muster instance.'
> subscribe ref('name')
Subscription 1:  value({value: "Bob"})
'Subscription "1" opened'
> set('name', 'Jane')
Subscription 1:  value({value: "Jane"})
'value({value: "Jane"})'
> unsubscribe 1
'Subscription "1" closed.'

Named subscriptions

Muster version: 5.0.0-rc.6
Muster REPL version: 5.0.0-rc.6

> muster({ name: variable('Bob') })
'Created a new muster instance.'
> subscribe:userName ref('name')
Subscription userName:  value({value: "Bob"})
'Subscription "userName" opened'
> unsubscribe userName
'Subscription "userName" closed.'

List open subscriptions

Muster version: 5.0.0-rc.6
Muster REPL version: 5.0.0-rc.6

> subscriptions
'No open subscriptions.'
> subscribe value('asdf')
Subscription 1:  value({value: "asdf"})
'Subscription "1" opened'
> subscriptions
ID "1": value('asdf')
Last value: value({value: "asdf"})
undefined

Load external muster graph

Given a graph.js:

module.exports = muster({
  firstName: variable('Jane'),
  lastName: variable('Doe'),
  fullName: computed(
    [ref('firstName'), ref('lastName')],
    (firstName, lastName) => `${firstName} ${lastName}`,
  ),
});

You can load that file in REPL:

Muster version: 5.0.0-rc.7
Muster REPL version: 5.0.0-rc.7

> load ~/Desktop/graph.js
Loaded muster instance.
> ref('firstName')
value({value: "Jane"})
> ref('lastName')
value({value: "Doe"})