[SalesForce] Can we call LWC wire adapters imperatively

Is it possible to call a wire adapter such as getObjectInfo imperatively? I know they return void and not a Promise so surely they can't be called like an Apex method. This is the error I've been getting:

LWC component's @wire target property or method threw an error during value provisioning. Original error:
[this.callback is not a function]]

Example call I've tried:

method() {
    getObjectInfo({ objectApiName: 'Account' });
}

If this is not possible is there any way I could utilize the LDS adapters imperatively as opposed to resorting to Apex? In my case I want to retrieve a list of fields for an object, on demand.

Best Answer

No, wire methods cannot be called imperatively.

Use Apex in these scenarios:

...

To call a method imperatively, as opposed to via the wire service. You may want to call a method imperatively in response to clicking a button, or to delay loading to outside the critical path. When you call an Apex method imperatively, to refresh the data, invoke the Apex method again.

If you need to do some special handling afterwards, set this up in the wire handler:

@wire(method, params) 
 wireHandler({data,error}) {
  if(data) {
   this.handleData(data);
  }
  if(error) {
   this.handleError(error);
  }
 }

To actually trigger the call, you can set a reactive variable:

someVariable;
@wire(method, {param:'$someVariable'})

If you wanted to further make the call dynamic, you can do that, too!

someVariable;
someCallback;
@wire(method, {param:'$someVariable'}) 
 wireHandler({data,error}) {
  if(data) {
   this.someCallback(data);
  }
  if(error) {
   this.handleError(error);
  }
 }
 handleClick(event) {
  this.someCallback = (result) => {
   console.log(result);
  };
  this.someVariable = 'Hello World';
 }

Related Solutions

[SalesForce] Chain wire methods together in Lightning Web Components

You have to use dynamic binding:

@wire(getPicklistValues, {recordTypeId: "$rtId", fieldApiName: TYPE_FIELD})
picklistValues;

This is mentioned in Use the Wire Service to Get Data.

I wrote a mockup that demonstrates this. You should be able to copy-paste this code directly.

<template>
    <template if:true={hasPicklistValues}>
        <select>
            <template for:each={picklistValues.data.values} for:item="entry">
                <option key={entry.value} value={entry.label}>{entry.label}</option>
            </template>
        </select>
    </template>
</template>

import { LightningElement, wire, track } from 'lwc';
import { getPicklistValues, getObjectInfo } from 'lightning/uiObjectInfoApi';
import TYPE_FIELD from '@salesforce/schema/Account.Type';
import ACCOUNT_OBJECT from '@salesforce/schema/Account';


export default class Democomponent extends LightningElement {
    @track rtId;
    @track error;

    @wire(getObjectInfo, { objectApiName: ACCOUNT_OBJECT })
    handleResult({error, data}) {
        if(data) {
            this.rtId = data.defaultRecordTypeId;
        } else {
            this.error = error;
        }
    }

    @wire(getPicklistValues, {recordTypeId: "$rtId", fieldApiName: TYPE_FIELD})
    picklistValues;

    get hasPicklistValues() {
        return this.picklistValues && this.picklistValues.data && this.picklistValues.data.values;
    }
}

[SalesForce] I’m getting this error: LWC component’s @wire target property or method threw an error during value provisioning

Welcome to SF Stack Exchange.

You are likely getting this error because an error must have occurred during your wire process.

From the documentation:

data (Any type)—The value supplied by the adapter.

error (Error)—An error if the adapter wasn’t able to supply the requested data or if the adapter wasn’t found. Otherwise, this property is undefined.

In this case the error object came back instead of the data. Essentially since data did not come back your code attempts to execute undefined.lists which throws the error [Cannot read property 'lists' of undefined] you are seeing.

What you need to do is add an if statement to verify if data came back or not like so:

@wire(getListUi, {objectApiName: PRODUCT_OBJECT})
wiredlistView({error,data}) {
    if (data) {
        this.allListViews = data.lists;
        var listViewData = [];
        for(var i=0;i<this.allListViews.length;i++){
            listViewData.push({"label" : this.allListViews[i].label, "value" : this.allListViews[i].apiName});
    } else if (error) {
        console.log('An error has occurred:');
        console.log(error);
        // handle your error.
    }
}

Best Answer

Related Solutions

[SalesForce] Chain wire methods together in Lightning Web Components

[SalesForce] I’m getting this error: LWC component’s @wire target property or method threw an error during value provisioning

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