Fixing Uninitialized Variable Errors in TypeScript
Learn about strictNullChecks and strictPropertyInitialization options in TypeScript, which identify uninitialized variables and suggest error fixes.
The strictNullChecks option
The strictNullChecks compiler option is used to find instances in our code where
the value of a variable could be null or undefined at the time of usage. This means that when the variable is actually used if it has not been properly initialized, the compiler will generate an error message.
Consider the following code:
let a: number;let b = a;
Here, we define a variable named a that is of type number. We then define a variable named b and assign the value of a to it. This code will generate an error.
This error tells us that we are attempting to use the value of the variable a before it has been assigned a value.
Remember that because it has not yet been assigned a value, it could still be undefined. There are two ways to remove this error message.