Jun 082017

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Flow: How to read a value from some Flow instance?

This blog post describes an approach on reading a value from an instance of Flow component in Total.js controller.

Flow: How to read a value from an instance of Flow component?

Total.js Flow is really great tool and this tutorial shows you how you can get an instance of component from Total.js Flow directly in a controller.

Follow these steps:

create your own flow with analytics component
double-click on analytics component and type a reference to mystats and press save (as the picture below)

Analytics settings

Then create a controller controllers/default.js:

exports.install = function() {
    F.route('/', readfromflow);
};

function readfromflow() {

    // FLOW is a global variable defined in FLOW package
    var instance = FLOW.findByReference('mystats')[0];
    if (!instance)
        return this.throw404();

    // instance === Flow "Analytics" Instance
    // Source-Code: https://github.com/totaljs/flowcomponents/blob/master/analytics/analytics.js#L142
    var current = instance.custom.current();

    // Renders serialized data in JSON format
    self.json(current, true);
}

Where can I read all public methods from Flow components?

Download Flow Components repository
open each component to see all public methods (defined as instance.custom.<method-name>)

Another helpful FLOW methods

FLOW.findByReference('STRING');
FLOW.findByReference(REGULAR_EXPRESSION);
// Finds all instances by reference
// returns {Array of Components}

FLOW.findByName('STRING');
FLOW.findByName(REGULAR_EXPRESSION);
// Finds all instances by name
// returns {Array of Components}

FLOW.findByComponent('STRING');
FLOW.findByComponent(REGULAR_EXPRESSION);
// Finds all instances by component name
// returns {Array of Components}

FLOW.findById('ID');
// Finds an instance by its ID
// returns {Component}

FLOW.hasComponent(name);
// Is component installed?
// returns {Boolean}

FLOW.hasInstance(id);
// Does an instance of component with the given id exists?
// returns {Boolean}

Flow: How to read a value from an instance of Flow component?

Where can I read all public methods from Flow components?

Another helpful FLOW methods

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