World Factbook

1) Get a button for each letter

• Show a button for each letter that a country can begin with
• You can use a Set to remove duplicates from a list.

Input

fetch('/worldl.json') .then((r)=>r.json()) .then((r)=>{ let letters = r.map(c=>c.name[0]); for(let a of letters){ let b = document.createElement('button'); b.innerText = a; document.body.append(b); } });

xxxxxxxxxx

 

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fetch('/worldl.json')

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  .then((r)=>r.json())

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  .then((r)=>{

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     let letters = r.map(c=>c.name[0]);

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     for(let a of letters){

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       let b = document.createElement('button');

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       b.innerText = a;

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       document.body.append(b);

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     }

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  });

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​

Go reset

Output

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let letters = r.map(c=>c.name[0]);
     for(let a of letters){
       let b = document.createElement('button');
       b.innerText = a;
       document.body.append(b);
     }
  });

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let letters = new Set(r.map(c=>c.name[0]));
     for(let a of letters){
       let b = document.createElement('button');
       b.innerText = a;
       document.body.append(b);
     }
  });

2) Get a button for each continent

• Show a button for each continent

Input

1

 

1

​

Go reset

Output

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let letters = new Set(r.map(c=>c.continent));
     for(let a of letters){
       let b = document.createElement('button');
       b.innerText = a;
       document.body.append(b);
     }
  });

3) Pick a random country from Africa

• Use Math.random() to pick a country at random
• Note that because of the way the scoring works you should not expect to get 100%

The sample code shows a random country beginning with 'A'

Input

fetch('/worldl.json') .then((r)=>r.json()) .then((r)=>{ let alist = r.filter(c=>c.name[0]==='A'); let randomNumber = Math.floor(Math.random()*alist.length); let randomCountry = alist[randomNumber]; document.body.innerText = randomCountry.name; });

xxxxxxxxxx

 

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fetch('/worldl.json')

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  .then((r)=>r.json())

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  .then((r)=>{

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     let alist = r.filter(c=>c.name[0]==='A');

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     let randomNumber = Math.floor(Math.random()*alist.length);

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     let randomCountry = alist[randomNumber];

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     document.body.innerText = randomCountry.name;

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  });

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​

Go reset

Output

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let alist = r.filter(c=>c.name[0]==='A');
     let randomNumber = Math.floor(Math.random()*alist.length);
     let randomCountry = alist[randomNumber];
     document.body.innerText = randomCountry.name;
  });

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let africa = r.filter(c=>c.continent==='Africa');
     let randomNumber = Math.floor(Math.random()*africa.length);
     let randomCountry = africa[randomNumber];
     document.body.innerText = randomCountry.name;
  });

4) Pick four random countries

• A large country is one with a population of at least 100 million
• Pick four large countries, without repetition

Bangladesh
Brazil
China
India
Indonesia
Japan
Mexico
Nigeria
Pakistan
Russia
United States

Input

fetch('/worldl.json') .then((r)=>r.json()) .then((r)=>{ let alist = r.filter(c=>c.population >= 100000000); for(let c of alist){ c.rand = Math.random(); } alist.sort((a,b)=>a.rand-b.rand); for(let i=0;i<alist.length;i++){ let d = document.createElement('div'); d.innerText = alist[i].name; document.body.append(d); } });

xxxxxxxxxx

 

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fetch('/worldl.json')

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  .then((r)=>r.json())

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  .then((r)=>{

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     let alist = r.filter(c=>c.population >= 100000000);

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     for(let c of alist){

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       c.rand = Math.random();

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     }

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     alist.sort((a,b)=>a.rand-b.rand);

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     for(let i=0;i<alist.length;i++){

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       let d = document.createElement('div');

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       d.innerText = alist[i].name;

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       document.body.append(d);

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     }

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  });

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​

Go reset

Output

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let alist = r.filter(c=>c.population >= 100000000);
     for(let c of alist){
       c.rand = Math.random();
     }
     alist.sort((a,b)=>a.rand-b.rand);
     for(let i=0;i<alist.length;i++){
       let d = document.createElement('div');
       d.innerText = alist[i].name;
       document.body.append(d);
     }
  });

fetch('/worldl.json')
  .then((r)=>r.json())
  .then((r)=>{
     let alist = r.filter(c=>c.population >= 100000000);
     for(let c of alist){
       c.rand = Math.random();
     }
     alist.sort((a,b)=>a.rand-b.rand);
     for(let i=0;i<4;i++){
       let d = document.createElement('div');
       d.innerText = alist[i].name;
       document.body.append(d);
     }
  });