const a: any = someValue !;

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP



const a: any = someValue !;



I studied the source code of the mechanism changeDetaction in angular6 and came across an interesting design that neither I nor the guys from work know, The code here, does anyone know what it is or how it works? Specifically, line 60:


changeDetaction


let changes: SimpleChanges = undefined !;




1 Answer
1



If you take a look at the history of the file (e.g. blame view), you will find out how this line came into existence:



fix(core): Update types for TypeScript nullability support (#15472)



You will find the the non-null assertion operator in the TypeScript design notes which introduces



A new ! postfix expression-level operator.


!



It tells the compiler, that the value (and property) cannot be null. See also these related stackoverflow questions and answers:






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