Best Practice - Where to place JavaScript

[HS_Nico]

Hello everyone,

what is your experience with JavaScript in PowerApps? Where is the best place to put my code, in which scenario? My goal is not to have to paste the same code twice.

Example 1: Business Process Flows
Can you store code globally for a BPF? E.g. to show or hide the create button (https://docs.microsoft.com/en-us/power-apps/developer/model-driven-apps/clientapi/reference/formcont... ).

Example 2: columns/form fields
Multi-selection option fields are not supported by business rules. However, you can implement the desired rule with JavaScript. Is there a way to assign this code to the appropriate column so that it is active in every form.

Alternatively, the code of the two examples would have to be stored in every form that works with the BPF or the column.

I look forward to feedback
Nico

[SBax]

I use a helper script to hold my commonly used functions.

For example I have a script that sends a HTTP request, another that shows/hides a section based on a defined criteria, and other functions that I use in multiple places.

I then create a function in whichever relevant location(s) to simply call the function from my helper script and pass in the required inputs 

Hopefully this makes sense, if not, let me know and I'll share some screenshots of the helper script, and an example function to call one of the functions from the helper script

[HS_Nico]

Many thanks for your response.

I would be very happy to see more details (screenshots, examples) of your solution.

[SBax]

I will upload an example later today, most likely on my lunch break 

[SBax · Accepted solution]

Helper Script:

// helper functions
'use strict';
var cdmtHelper = window.cdmtHelper || {};
(function () {
	//required for refreshing ESRI map
	// refresh web resource
	this.refreshIframe = function (executionContext, controlName) {
		var formContext = executionContext.getFormContext();
		var control = formContext.getControl(controlName);

		if (control !== null) {
			var iFrame = control.getObject();

			if (iFrame !== null) {
				iFrame.contentDocument.location.reload(true);
			}
		}
	};

	//required for Map.HTML
	// get data parameter from query string, e.g. in HTML web resource
	this.getDataParameter = function () {
		return decodeURIComponent(cdmtHelper.getUrlParameter('data'));
	};

	//required for Map.HTML
	// get parameter from URL
	this.getUrlParameter = function (name) {
		name = name.replace(/[\[]/, '\\[').replace(/[\]]/, '\\]');
		var regex = new RegExp('[\\?&]' + name + '=([^&#]*)');
		var results = regex.exec(location.search);
		return results === null
			? ''
			: decodeURIComponent(results[1].replace(/\+/g, ' '));
	};

	//required for Map.HTML
	// function to fetch records recursively in batches
	this.retrieveMultipleRecordsRecursive = function (
        webApi,
        entityLogicalName,
        options,
        maxPageSize
    ) {
        var totalEntities = [];

        return new Promise(function (resolve, reject) {
            var resolution = function (result) {
                // add current batch to the total array
                totalEntities = totalEntities.concat(result.entities);

                // if more results to be retrieved
                if (result.nextLink) {
                    var nextLinkOptions = "?" + result.nextLink.split("?")[1];
                    cccHelper
                        .retrieveMultipleRecordsRecursive(
                            webApi,
                            entityLogicalName,
                            nextLinkOptions,
                            maxPageSize
                        )
                        .then(resolution, reject);
                }

                // if no more results to be retrieved
                else {
                    resolve({ entities: totalEntities });
                }
            };

            webApi
                .retrieveMultipleRecords(
                    entityLogicalName,
                    options,
                    maxPageSize
                )
                .then(resolution, reject);
        });
    };

	//required for Create Document from Template feature
	this.sendHttpRequestPromise = function (url, data, method, headers) {
		return new Promise(function (resolve, reject) {
			if (method === null || method === undefined) {
				method = 'GET';
			}

			if (headers === null || headers === undefined) {
				headers = [['Accept', 'application/json']];
			}

			var req = new XMLHttpRequest();
			req.open(method, url, true);

			// set request headers
			for (var headerName in headers) {
				if (headers.hasOwnProperty(headerName)) {
					req.setRequestHeader(headerName, headers[headerName]);
				}
			}

			req.onreadystatechange = function () {
				// if complete
				if (req.readyState === 4) {
					// if 200 OK
					if (req.status === 200) {
						resolve(req);
					}

					// if 204 No Content
					else if (req.status === 204) {
						resolve(req);
					}

					// otherwise
					else {
						reject(req);
					}
				}
			};
			req.send(data);
		});
	};

	this.executeFlowFromEV = function (varName, recordID, progressMessage) {
		return new Promise((resolve, reject) => {
			Xrm.Utility.showProgressIndicator(progressMessage);
			cdmtHelper.getEnvironmentVariable(varName).then(
				function (flowUrl) {
					cdmtHelper.executeFlow(flowUrl, recordID).then(
						function () {
							Xrm.Utility.closeProgressIndicator();
							resolve();
						},
						function () {
							Xrm.Utility.closeProgressIndicator();
							reject();
						}
					);
				},
				function () {
					Xrm.Utility.closeProgressIndicator();
					reject();
				}
			);
		});
	};

	this.executeFlow = function (flowUrl, recordID) {
		'use strict';

		//do something here
		return new Promise((resolve, reject) => {
			const input = JSON.stringify({
				id: recordID.replace('{', '')?.replace('}', ''),
			});
			const req = new XMLHttpRequest();
			req.open('POST', flowUrl, true);
			req.setRequestHeader('Content-Type', 'application/json');
			req.send(input);
			req.onreadystatechange = function () {
				'use strict';
				if (this.readyState === 4) {
					req.onreadystatechange = null;
					//if response is 200
					if (this.status === 200) {
						resolve();
					} else {
						reject();
					}
				}
			};
		});
	};

	// Returns a promise to retrieve the given environment variable's value
	this.getEnvironmentVariable = function (varName, currentValue) {
		return new Promise(function (resolve, reject) {
			// If value has been retrieved already
			if (currentValue !== undefined) {
				// Don't bother retrieving again
				resolve(currentValue);
			} else {
				// Retrieve environment variable record
				Xrm.WebApi.retrieveMultipleRecords(
					'environmentvariabledefinition',
					`?$top=1&fetchXml=<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='true'>
                            <entity name='environmentvariabledefinition'>
                                <attribute name='defaultvalue' />
                                <filter type='and'>
                                    <condition attribute='schemaname' operator='eq' value='${varName}' />
                                </filter>
                                <link-entity name='environmentvariablevalue' from='environmentvariabledefinitionid' to='environmentvariabledefinitionid' link-type='outer' alias='varvalue'>
                                    <attribute name='value' />      
                                </link-entity>
                            </entity>
                        </fetch>`
				).then(function (result) {
					if (result.entities.length === 0) {
						reject(`Environment variable "${varName}" not found.`);
					} else {
						var environmentVariable = result.entities[0];

						if (typeof environmentVariable['varvalue.value'] !== 'undefined') {
							resolve(environmentVariable['varvalue.value']);
						} else if (
							typeof environmentVariable.defaultvalue !== 'undefined'
						) {
							resolve(environmentVariable.defaultvalue);
						} else {
							reject(
								`Environment variable "${varName}" does not contain a value.`
							);
						}
					}
				}, reject);
			}
		});
	};
	//function to open a form as a dialog

	this.openDialog = function (
		FirstSelectedItemId,
		SelectedEntityTypeName,
		HeightValue,
		WidthValue,
		PostionValue
	) {
		const pageInput = {
			pageType: 'entityrecord',
			entityName: SelectedEntityTypeName, //uses the entiyty type of the record selected in your subgrid
			entityId: FirstSelectedItemId, //uses the id of the record you have selected
		};
		const navigationOptions = {
			target: 2, //show on top of current record
			height: { value: HeightValue, unit: '%' }, //controls hieght of dialog
			width: { value: WidthValue, unit: '%' }, //controls width of dialog
			position: PostionValue, //1 = centre of screen, 2 = right of screen
		};

		Xrm.Navigation.navigateTo(pageInput, navigationOptions);
	};
}.call(cdmtHelper));

Form Script:

function cancelSlot(primaryControl, environmentVariableName) {
	const formContext = primaryControl;
	const recordId = formContext.data.entity
		.getId()
		.replace('{', '')
		.replace('}', '');

	cdmtHelper
		.executeFlowFromEV(
			environmentVariableName,
			recordId,
			'Slot cancellation in progress...'
		)
		.then(
			function () {
				const alertStrings = {
					confirmButtonLabel: 'OK',
					text: 'Slot Cancellation Successful',
					title: 'Information',
				};
				const alertOptions = { height: 120, width: 260 };
				Xrm.Navigation.openAlertDialog(alertStrings, alertOptions).then(
					function confirmButtonPressed() {
						formContext.data.refresh(true);
					},
					function dialogClosed() {
						formContext.data.refresh(true);
					}
				);
			},

			function () {
				const alertStrings = {
					confirmButtonLabel: 'OK',
					text: 'Slot Cancellation Failed',
					title: 'Information',
				};
				const alertOptions = { height: 120, width: 260 };
				Xrm.Navigation.openAlertDialog(alertStrings, alertOptions).then(
					function confirmButtonPressed() {
						formContext.data.refresh(true);
					},
					function dialogClosed() {
						formContext.data.refresh(true);
					}
				);
			}
		);
}

Basically the helper script holds my reusable code, the form scipt calls that piece of code, and passes in parameters required for the function to run

[HS_Nico]

How do you make your helper script available globally? I am assuming you are uploading the files as web resources. But that doesn't automatically run the code. Or do you load the helper script in each form individually?

[SBax]

Hi @HS_Nico 

I add the helper script on the forms that call functions from it