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Javascript Control Flow

Equality

• Triple Equals

  1 === 1;
 

Checks type and value
• Double Equals

  1 == 1;
 

checks only values
• Weird Examples

  0 == "0"         // true
  0 == ""          // true
  0 == []          // true
  

however,

  0 == null        // false
  0 == undefined   // false
   

and,

  "true"  == true  // false
  "false" == false // false
   

If you want to check:

  5 == "5";
  

better do:

  5 === Number("5");
   

• Truthy or Falsy?

  ""       // falsy
  []       // truthy
  ()       // truthy
  NaN      // falsy
  Infinity // falsy
  0        // falsy
  

more confusing shizer:

         "" == false      // true
          0 == false      // true
         0n == false      // true
        Nan == false      // false
       null == false      // false
  undefined == false      // false
  

• memorize the 7 falsy values

• ""
• 0
• 0n
• NaN
• undefined
• null
• false

null == null              // true
null == false             // false
null == true              // false
   

Objects

  Obj1 === obj2   // always false
  

unless they are literally the same object. }

If Statements

  let condition  = true;
  let condition2 = false;
  if (condition) {
  console.log("Do action");
  } else if (condition2) {
  console.log("take alternative actions");
  } else {
  console.log("take default action");
  }

http:///wiki/?jscontrolflow

11apr23

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