type-safety

what’s type safety?

tags: learning programming

content

• type safety means the programming language prevents you from doing operations on a value that’s not valid for its type
• a type-safe language doesn’t allow you to call a method that does not exist on a type

var a = 1;
var b = "test";
a = a + b;  // this is allowed because js is dynamically typed
a.toUpperCase()  // a is now "1test"

• if b is another int, the program will crash at runtime, because there’s no toUpperCase method for type int
• toUpperCase is valid for type string, but not valid for type int

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