Test Your JavaScript Skills : ES11 (JavaScript 2020) - 41

Introduction

Namaste, In this blog I will discuss 8 code scenarios on Javascript .

1. Identify the output of the below program

    // mymath.mjs
    export function add(a,b) {
        return a+b;
    }
   
    // program.js
    let mod = './mymath.mjs'
    import(mod).then (arg => {
        console.log("module loaded");
    }).catch(err => {
        console.log("Error");
    });
   

   a. 10

   b. 0

   c.module loaded

   d.crash

   e.Error

   Answer:c

   Reason:The given module is loaded.

2. Identify the output of the below program

    let prm = [
        Promise.resolve("success")
    ];
   
    Promise.allSettled(prm).then (arg => {
        console.log(arg[0].value);
    });
   

   a.success

   b.failure

   c.fulfilled

   d.error

   e.undefined

   Answer:a

   Reason:The promise returns the value success.

3. Identify the output of the below program

    let prm = [
        Promise.resolve("success"),
        Promise.reject("failed")
    ];
   
    Promise.allSettled(prm).then (arg => {
        console.log(arg[1].reason);
    });
   

   a.success

   b.failed

   c.fulfilled

   d.undefined

   e.error

   Answer:b

   Reason:The promise returns the reason - failed.

4. Identify the output of the below program

   
    Promise.allSettled([
        Promise.resolve("ram"),
        new Promise((resolve) => setTimeout(() => resolve(100), 4000)),
        true,
        Promise.reject(new Error("an error")),
      ]).then((values) => {
        console.log(values[2].value);    
      });
   

   a.ram

   b.100

   c.true

   d.undefined

   e.an error

   Answer:c

   Reason:The promise returns the value true.

5. Identify the output of the below program when the program is executed on Node.js

    console.log(globalThis===global);
   

   a.true

   b.false

   c.error

   d.undefined

   e.0

   Answer:a

   Reason:Both the objects are identical

6. Identify the output of the below program

   
    Promise.allSettled([
        Promise.resolve("ram"),
        new Promise((resolve) => setTimeout(() => resolve(100), 4000)),
        true,
        Promise.reject(new Error("an error")),
      ]).then((values) => {
        console.log(values[1].value);    
      });
   

   a.100

   b.true

   c.ram

   d.an error

   e.undefined

   Answer:a

   Reason:The promise returns the value 100.

7. Identify the output of the below program

    // mymath.mjs
    export function add(a,b) {
        return a+b;
    }
   
    // program.js
    let mod = './math.mjs'
    import(mod).then (arg => {
        console.log("module loaded");
    }).catch(err => {
        console.log("error");
    });
   

   a.module loaded

   b.error

   c.undefined

   d.no output

   e.1

   Answer:b

   Reason:The name of the module is incorrect hence there is an error.

8. Identify the output of the below program

   
    Promise.allSettled([
        Promise.resolve("ram"),
        new Promise((resolve) => setTimeout(() => resolve(100), 4000)),
        true,
        Promise.reject("error"),
      ]).then((values) => {
        console.log(values[3].reason);    
      });
   

   a.ram

   b.100

   c.true

   d.error

   e.undefined

   Answer:d

   Reason:The promise fails hence the reason is error.