Custom Functions

easy-api.ts lets you add custom functionality to the library, that’s why creating custom functions is a thing.

Creating your first custom function

We need to require the following classes and enums from the library.

var { APIFunction, ParamType } = require("easy-api.ts");

Now, let’s extend the APIFunction class. We will make an owoify function for this example.

class AnyName extends APIFunction {
    name = "owoify";
    description = "Owoifies a message.";
    parameters = [{
        name: "Message",
        description: "The message to be owoified.",
        type: ParamType.String,
        required: true,
        rest: false,
        defaultValue: null
    }]; // It's important to fill this array if your function has parameters.
    usage = "$owoify[message]";
    returns = ParamType.String;
    compile = true;
    aliases = [];
    async run(d, [message]) {
        return message.replace(
            /[rl]/gi,
            (match) => /[RL]/.test(match) ? "W" : "w"
        );
    }
};

Now, let’s export your custom function.

exports.default = AnyName;

Loading your custom function

To load your custom function, you can use the load method of the function manager.

var api = new API(...);

api.functions.load("<path to function>");

Scoped-functions Advanced

Scoped-functions are functions that can be executed in certain function scopes. This is appliable for $case and $switch or canvas functions.

This is an easy-to-understand concept, but first, we need to comprehend what an scope is.

Understanding scopes

“Scopes” refer to the contexts in which variables are accessible. Let’s define a global variable.

$let[myAwesomeVar;13]

You can access this variable in the whole code.

$if[$get[myAwesomeVar;...]]
$createCanvas[
    $setDimensions[12;32]
    $switch[7;
        $case[$get[myAwesomeVar];...]
    ]
]

You change the value of a variable in a child scope and it will updated in the parent scope.

$let[myAwesomeVar;13]
^ now var is "13".

$createCanvas[
    $setDimensions[12;32]
    $let[myAwesomeVar;32]
    ^ now var is "32".
]

$get[myAwesomeVar]
^ var is still "32".

Now, let’s define an scoped variable.

$let[myAwesomeVar;13]
^ now var is "13".

$scope[
    $let[idx;16]
    ^ now var is "16".

    $let[idx;24]
    ^ now var is "24".
;true]

$get[idx]
^ ERROR: undefined variable.

$get[myAwesomeVar]
^ returns: "13".

Some functions can’t inherit data from parent scopes.

Creating the parent function

You can follow the existing guide for this step in “Creating your first custom function”.

const { API, APIFunction, Data, ParamType, Util } = require("easy-api.ts");

exports.default = class ParentFunc extends APIFunction {
    name = "$map";
    description = "Maps the given numbers and load the results to a variable.";
    parameters = [{
        name: "Numbers",
        description: "Numbers separated by commas.",
        type: ParamType.Number,
        required: true,
        rest: false,
        defaultValue: null
    },{
        name: "Code",
        description: "Code to be applied to each number.",
        type: ParamType.String,
        required: true,
        rest: false,
        defaultValue: null
    }]
    usage = "$map[3,6,9,12;$load[uwu;%element%]]"
    compile = false // Important to set to false.
    aliases = []
    async run(d, [numbers, code]) {
        /**
         * We are extending Data to create a sub-data and attach the scoped-function
         * to this cloned data without affecting the parent one.
         * (allow the execution for the subdata but not for the parent because
         * function doesn't exists there.)
         *
         * First parameter are environment variables you create with $let[]
         * Second parameter are internal variables that ea.ts uses "to work under the hood".
         */
        const data = d.extend(d._, d.__);

        // Now load your function source.
        data.functions.load(__dirname, (fn) => typeof fn.parent !== "undefined" && fn.parent === this.name);

        /**
         * Now resolve the function argument using an util method.
         * We pass as first parameter, the cloned data where the function exists
         * and as second param the code to be parsed.
         */
        const result = await Util.resolveCode(data, content);

        // We return the result.
        return result;
    }
};

Creating the scoped function

exports.default = class SubFunc extends APIFunction {
    name = "$load";
    description = "Loads the result to a variable.";
    parameters = [{
        name: "Name",
        description: "Variable name to load the value to.",
        type: ParamType.String,
        required: true,
        rest: false,
        defaultValue: null
    },{
        name: "Value",
        description: "Value to be loaded to the variable.",
        type: ParamType.String,
        required: true,
        rest: false,
        defaultValue: null
    }]
    usage = "$load[name;value]"
    compile = true
    aliases = []
    async run(d, [name, value]) {
        d.setVar(name, value)
    }
};

Using our custom function

$map[1,2,3,4,5,6;
    $load[res;$sum[%element%;3]]
]
^ works fine.

$map[1,2,3,4,5,6;
    $log[%element%;3]
]
$load[res;$sum[%element%;3]]
^ ERROR: $load is not a function.