Executing asynchronous functions within synchronous functions in TypeScript and returning a boolean value

Question

Executing asynchronous functions within synchronous functions in TypeScript and returning a boolean value

Is there a way to call an asynchronous function from a synchronous function without encountering issues?

function showOpenCaseDialog(): boolean {

    let result = false;

    var regardingobjectid = (<Xrm.LookupAttribute<string>>Xrm.Page.getAttribute("regardingobjectid")).getValue();
    if (regardingobjectid != null && regardingobjectid.length > 0) {
        var regardingobject = regardingobjectid[0];
        if (regardingobject.entityType === "incident") {
            checkCaseLastOpenActivity(regardingobject).then(x => result = x);
        }
    }

    return result;
};

The function checkCaseLastOpenActivity is asynchronous in nature.

One issue encountered is that the synchronous function returns a value before the asynchronous operation is completed.

Are there any potential solutions to this problem?

typescript asynchronous synchronous

Answer 1

Answer №1

Even though the code appears to be synchronous, it is actually functioning asynchronously.

Consider making the showOpenCaseDialog function an async function that returns a Promise<boolean>.

async function showOpenCaseDialog(): Promise<boolean> {

    let result = false;

    var regardingobjectid = (<Xrm.LookupAttribute<string>>Xrm.Page.getAttribute("regardingobjectid")).getValue();
    if (regardingobjectid != null && regardingobjectid.length > 0) {
        var regardingobject = regardingobjectid[0];
        if (regardingobject.entityType === "incident") {
            result = await checkCaseLastOpenActivity(regardingobject);
        }
    }

    return result;
};

Answer 2

Even though the code appears to be synchronous, it is actually functioning asynchronously.

Consider making the showOpenCaseDialog function an async function that returns a Promise<boolean>.

async function showOpenCaseDialog(): Promise<boolean> {

    let result = false;

    var regardingobjectid = (<Xrm.LookupAttribute<string>>Xrm.Page.getAttribute("regardingobjectid")).getValue();
    if (regardingobjectid != null && regardingobjectid.length > 0) {
        var regardingobject = regardingobjectid[0];
        if (regardingobject.entityType === "incident") {
            result = await checkCaseLastOpenActivity(regardingobject);
        }
    }

    return result;
};

Answer 3

Answer №2

If you want to leverage ES6 promises, give it a shot.

Wrap the async section in a promise and handle the return in the then block. See the example below:

var promise1 = new Promise(function(resolve, reject) { resolve(Xrm.Page.getAttribute("regardingobjectid").getValue()); });

promise1.then(function(regardingobjectid) {
    if (regardingobjectid != null && regardingobjectid.length > 0) {
        var regardingobject = regardingobjectid[0];
        if (regardingobject.entityType === "incident") {
            checkCaseLastOpenActivity(regardingobject).then(x => result = x);
        }
    }
});

Alternatively, you can directly return the promise from the function as needed.

For more in-depth information, check out https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

Answer 4

If you want to leverage ES6 promises, give it a shot.

Wrap the async section in a promise and handle the return in the then block. See the example below:

var promise1 = new Promise(function(resolve, reject) { resolve(Xrm.Page.getAttribute("regardingobjectid").getValue()); });

promise1.then(function(regardingobjectid) {
    if (regardingobjectid != null && regardingobjectid.length > 0) {
        var regardingobject = regardingobjectid[0];
        if (regardingobject.entityType === "incident") {
            checkCaseLastOpenActivity(regardingobject).then(x => result = x);
        }
    }
});

Alternatively, you can directly return the promise from the function as needed.

For more in-depth information, check out https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

Answer 5

Answer №3

executeAsyncOperation(param1, cb: (result)=> void) : any {
.....
this._backendRequest.makeRequest(param1)
 .subscribe(response=>{
 .......
 .......
 return cb(response);
  });
}

Example of using callback:

this.executeAsyncOperation(data1, (result)=>{
........
........
});

Example of using without callback:

this.executeAsyncOperation(data1, null);

Answer 6

executeAsyncOperation(param1, cb: (result)=> void) : any {
.....
this._backendRequest.makeRequest(param1)
 .subscribe(response=>{
 .......
 .......
 return cb(response);
  });
}

Example of using callback:

this.executeAsyncOperation(data1, (result)=>{
........
........
});

Example of using without callback:

this.executeAsyncOperation(data1, null);

Executing asynchronous functions within synchronous functions in TypeScript and returning a boolean value

Answer №1

Answer №2

Answer №3

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