jahmin
Version:
A JavaScript framework to build browser friendly Human Machine Interfaces for automation
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JavaScript
import { StateVariable } from "impera-js";
import { systemVariable, VarStatusCodes } from "./Types.js";
import { escape as escapeHtml } from 'html-escaper';
// NOTE:
// There are plenty of way of doing this, here we chose to have a single
// object representing the whole App state. If one have many var and many
// subsystems it can be heavy to write in localstorage all the time. It
// could be more efficient if split instead per subsystem (or even per
// single variables), to do so Impera-JS needs the additional capability
// of attaching a stateVar to an already instantiated object, without using
// a mixin. See issue: https://github.com/WebComponentHelpers/ImperaJS/issues/8
/**
* Class that contains all the data structure of the App for all the subsystems.
* The app state is saved in here.
* It is connected automatically to UI element and schedule updates on them.
*/
export class DataTree extends StateVariable {
constructor() {
super("datatree", {});
this.addTransition("create", this._create);
this.addTransition("update", this._update);
this.addTransition("multiupdate", this._multiupdate);
}
/**
* Get the current value and status of the related stateVariable.
* It returns a proxy to the real stateVariable, this is readonly, as a protection
* it will throw if you try to assign a value.
* @param {systemObject} varID - identifier of the variable, an object with keys (name,system)
*/
GetVar(varID) {
if (this.ExistVar(varID)) {
return this.value[varID.system][varID.name];
}
else
return null;
}
Create(varID) {
this.applyTransition("create", varID);
}
UpdateStatus(varID, _status) {
let upd_var = new systemVariable(varID);
upd_var.status = _status;
this.applyTransition("update", upd_var);
}
/**
* It upadtes with the variable or the list of variables.
* This will automatically call UI update of all connected elements.
* @param variables a list or a single systemVariable object with keys (name,system,status,value)
*/
Update(variables) {
if (Array.isArray(variables)) {
this.applyTransition("multiupdate", variables);
}
else {
this.applyTransition("update", variables);
}
}
_create(varID) {
if (varID && typeof varID.system === "string" && typeof varID.name === "string") {
varID.system = escapeHtml(varID.system);
varID.name = escapeHtml(varID.name);
let new_var = { status: null, value: null }; //new systemVariable(varID.name, varID.system);
new_var.status = VarStatusCodes.Pending;
if (!this.value.hasOwnProperty(varID.system))
this.value[varID.system] = {};
this.value[varID.system][varID.name] = new_var;
}
}
_multiupdate(sys_vars) {
sys_vars.forEach(input_var => {
this._update(input_var);
});
}
_update(varID) {
this._checkVarType(varID);
let sys_var = this.GetVar(varID);
if (!sys_var)
throw new Error("Requested Variable does not exist: " + varID.name);
if (typeof varID.value === 'string')
varID.value = escapeHtml(varID.value);
if (varID.status)
sys_var.status = escapeHtml(varID.status);
// carefull here as value can also be false for a boolean, so if(varID.value) does not work
if (varID.value !== null && varID.value !== undefined)
sys_var.value = varID.value;
}
_checkVarType(v) {
if (!v)
throw new TypeError("Variable cannot be null");
if (typeof v.name !== "string")
throw new TypeError("Variable Name must be a string");
}
/**
* Checks if the variable exist in the current state tree
* @param varID identifier of the variable, an object with keys (name,system)
*/
ExistVar(varID) {
if (typeof varID.system !== "string" && typeof varID.name !== "string")
return false;
if (!this.value.hasOwnProperty(varID.system))
return false;
if (!this.value[varID.system].hasOwnProperty(varID.name))
return false;
return true;
}
}