Way number three call apex method from javascript file ( Imperative call)

3.  Imperative way to communicate with the apex controller:

wireMethod.cmp :

<template>

    <lightning-card title="Apex Imperative" icon-name="standard:case">

        <div class="slds-m-around_small">

            <lightning-input value={priority}

            label="Search Cases accroding to Priorty"

            onchange={handleChange}

            name="pname"></lightning-input>

        </div>

        <div class="slds-m-around_small">

            <template for:each={records} for:item="item">

                <p key={item.Id}>

                    Case name : {item.Subject}<br/>

                    Case Description: {item.Description}<br/>

                    Case Priority : {item.Priority}<br/>

                    Case Origin : {item.Origin}<br/>

                    Case Status : {item.Status}<br/>

                    --------------------------------------

                </p>

            </template>

        </div>

    </lightning-card>

</template>

wireMethod.js:

import { LightningElement, track } from 'lwc';

import getAllCase from '@salesforce/apex/CaseController.getAllCase';

export default class ApexImperativeMethod extends LightningElement {

    @track records;

    @track error;

    handleChange(event){

        const pValue = event.target.value;

        getAllCase({

            priority: pValue

        })

        .then(result=>{

            this.records = result;

            console.log('Case Records : '+result);

        })

        .then(error=>{

            this.error = error;

            console.log("Error : "+error);

        })

    }

}

CaseController.apex :

public with sharing class CaseController {

    public CaseController() {

    }

    @AuraEnabled(cacheable=true)

    public static List<Case> getAllCase(String priority){

        return [

            Select Subject,Description,Status,Origin,Priority from Case where Priority =: priority

        ];

    }

}