# Test Your JavaScript Skills : ES9 (JavaScript 2018) - 44

## Introduction

Namaste, In this blog I will discuss 10 code scenarios on Javascript .

1. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.resolve(1);
        yield await Promise.resolve(2);
        yield await Promise.resolve(3);
      }
      
      let genobj = fx();
      genobj.next().then(v => console.log(v.value));
    ```
    
    **a.1**
    
    **b.2**
    
    **c.3**
    
    **d.undefined**
    
    **e.error**
    
    **Answer:a**
    
    **Reason:The return value is 1.**
    
2. **Identify the output of the below program**
    
    ```javascript
    
    async function* fx() {
        yield await Promise.resolve(100);  
      }
      
      let genobj = fx();
      genobj.next().then(v => console.log());
      genobj.next().then(v => console.log(v.done));
    ```
    
    **a.true**
    
    **b.false**
    
    **c.100**
    
    **d.undefined**
    
    **e.error**
    
    **Answer:a**
    
    **Reason:The return value is true.**
    
3. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.resolve(10);    
      }
      
      async function forawait() {
          for await (let obj of fx()) {
              console.log(obj);
          }
      }
      
      forawait();
    ```
    
    **a.10**
    
    **b.false**
    
    **c.true**
    
    **d.undefined**
    
    **e.error**
    
    **Answer: a**
    
    **Reason:The value is 10.**
    
4. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.resolve(10);    
      }
      
      async function forawait() {
          for await (let obj of fx()) {
              console.log(obj.done);
          }
      }
      
      forawait();
    ```
    
    **a.true**
    
    **b.false**
    
    **c.undefined**
    
    **d.error**
    
    **e.10**
    
    **Answer:c**
    
    **Reason:The done property does not exist.**
    
5. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.reject(10);    
      }
      
      async function forawait() {
          for await (let obj of fx()) {
              console.log(obj);
          }
      }
      
      forawait();
    ```
    
    **a.10**
    
    **b.undefined**
    
    **c.true**
    
    **d.false**
    
    **e.error**
    
    **Answer:e**
    
    **Reason:Because of unhandled rejection an error is raised.**
    
6. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.reject(10);    
      }
      
      async function forawait() {
        try {
          for await (let obj of fx()) {
              console.log(obj);
          }
        }catch (err) {
            console.log(err);
        }
      }
      
      forawait();
    ```
    
    **a.error**
    
    **b.undefined**
    
    **c.10**
    
    **d.true**
    
    **e.false**
    
    **Answer:c**
    
    **Reason:The rejected value 10 is captured in the catch block.**
    
7. **Identify the output of the below program**
    
    ```javascript
    
    async function* fx() {
        yield await Promise.resolve(1);
        yield await Promise.resolve(2);
        yield await Promise.resolve(3);
      }
      
      let genobj = fx();
      genobj.next().then(v => console.log(v.done));
    ```
    
    **a.1**
    
    **b.2**
    
    **c.true**
    
    **d.false**
    
    **e.error**
    
    **Answer:d**
    
    **Reason:The return value for done is false.**
    
8. **Identify the output of the below program**
    
    ```javascript
    
    async function* fx() {
        yield await Promise.resolve(100);  
      }
      
      let genobj = fx();
      genobj.next().then(v => console.log());
      genobj.next().then(v => console.log(v.value));
    ```
    
    **a.100**
    
    **b.error**
    
    **c.undefined**
    
    **d.1**
    
    **e.false**
    
    **Answer:c**
    
    **Reason:The return value is undefined.**
    
9. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.reject(1);    
      }
      
      let genobj = fx();
      genobj.next().then(v => console.log(v.value));
    ```
    
    **a.error**
    
    **b.undefined**
    
    **c.false**
    
    **d.true**
    
    **e.1**
    
    **Answer:a**
    
    **Reason:Because of unhandled rejection an error is raised.**
    
10. **Identify the output of the below program**
    
    ```javascript
    async function* fx() {
        yield await Promise.resolve(10);    
      }
      
      async function forawait() {
          for await (let obj of fx()) {
              console.log(obj.value);
          }
      }
      
      forawait();
    ```
    
    **a.10**
    
    **b.true**
    
    **c.false**
    
    **d.undefined**
    
    **e.error**
    
    **Answer:d**
    
    **Reason:The value property does not exist.**