scope problem should be updated to ES2015 #296

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1. ledsun commented on Feb 5, 2020

   

   ledsun

   on Feb 5, 2020

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   I agree.

   However, including the block scope feels a bit difficult.
   I would like to reduce the description of function scope and instead compare global scope with block scope.
2. itzsaga commented on Feb 5, 2020

   

   itzsaga

   on Feb 5, 2020

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   Yeah, having taught this to others I think removing function scope is okay for what javascripting is trying to achieve. We don't need to cover every part of JS and const & let are the most commonly used today IMO. Maybe a reference to var in the lesson so when people on their learning journey see it it's not a completely unknown.
3. rshpeley commented on Feb 5, 2020

   

   rshpeley

   on Feb 5, 2020

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   @ledsun here's a bit of code based on the scope problem to show global and block scoping:

   let [a, b, c] = [1, 2, 3]
   console.log(`a: ${a}, b: ${b}, c: ${c}`)
          
   {
     let [b, c] = [5, 6]
     console.log(`a: ${a}, b: ${b}, c: ${c}`)
     {
       let b = 8
       console.log(`a: ${a}, b: ${b}, c: ${c}`)
       {
         let [a, c] = [7, 9]
         console.log(`a: ${a}, b: ${b}, c: ${c}`)
         {
           let [a, c] = [1, 8]
           console.log(`a: ${a}, b: ${b}, c: ${c}`)
         }
         console.log(`a: ${a}, b: ${b}, c: ${c}`)
       }
       console.log(`a: ${a}, b: ${b}, c: ${c}`)
     }
     console.log(`a: ${a}, b: ${b}, c: ${c}`)
   }
   console.log(`a: ${a}, b: ${b}, c: ${c}`)

   Running node scope.js gives:

   a: 1, b: 2, c: 3
   a: 1, b: 5, c: 6
   a: 1, b: 8, c: 6
   a: 7, b: 8, c: 9
   a: 1, b: 8, c: 8
   a: 7, b: 8, c: 9
   a: 1, b: 8, c: 6
   a: 1, b: 5, c: 6
   a: 1, b: 2, c: 3
   

   Putting this into problem form:

   let [a, b, c] = [1, 2, 3]
          
   {
     let [b, c] = [5, 6]
     {
       let b = 8
       {
         let [a, c] = [7, 9]
         {
           let [a, c] = [1, 8]
         }
       }
     }
   }

   Then solution form:

   let [a, b, c] = [1, 2, 3]
          
   {
     let [b, c] = [5, 6]
     {
       let b = 8
       console.log(`a: ${a}, b: ${b}, c: ${c}`)
       {
         let [a, c] = [7, 9]
         {
           let [a, c] = [1, 8]
         }
       }
     }
   }

   Gives the proper solution.

   a: 1, b: 8, c: 6
   

   Of course the preamble still needs to be reworked.
4. ledsun commented on Apr 13, 2020

   

   ledsun

   on Apr 13, 2020

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   I am looking at another issue(#125) and wondering if the problem statement @rshpeley presented is too difficult.
5. ledsun

   added

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   on Apr 13, 2020