10. symbols | ES6 | JavaScript | TypeScript

10. symbols | ES6 | JavaScript | TypeScript

• 1.
  Symbols | ES6 JAGADEESHPATTA ( PJ )
• 2.
  Agenda  Introduction toSymbol  Symbol Syntax  Shared symbols in global registry.  Symbols in Object  Live examples
• 3.
  Introduction to Symbol Symbol is a primitive data type.  Symbols are created via a factory function.  No two symbols are equal Because each symbol has its own unique id.  Symbol has optional string-valued parameter (Description).  We can convert a symbol to string by using toString() method.
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  Symbol Syntax Syntax let symbol_name= Symbol ( Description ); // Description is an optional parameter. Example let sym = Symbol(“one”);
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  Shared Symbols inglobal registry Using Symbol ( ) factory function will not create a global symbol that is available in your hole codebase. Create a symbol in registry Symbol.for(“description”). Get Symbol from registry Symbol.keyFor(“description”)
• 6.
  Symbols in object We can use symbols as object keys.  By using Object.keys(obj) gives all keys of object as an array. But if the object uses symbols as keys this method will not work.  Object.getOwnPropertySymbols(obj) will gives you an iterator function. By using for..of we can get symbols one by one.
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  Symbols in object(cont…) Create Symbol In Object var obj = { Symbol(“name”) : “PJ”, Symbol(“name”) : “Jagadeesh Patta” }
• 8.
  Symbols in object(cont…) Get Symbols From Object var keys = Object.getOwnPropertySymbols( obj ); for ( let symbol of key){ console.log( obj[ symbol ] ); }
• 9.
  Any Q ?
• 10.
  Thank You