The ability to reach a variable beyond its block

As a newcomer to TypeScript (coming from the Java world), I am experimenting with creating a mapper function like this:

public getApercuTypePrestationFromTypePrestationEX044(typePrestationEX044: TypePrestationEX044): ApercuTypePrestation {
        let apercuTypePrestation: ApercuTypePrestation;
        if (null != typePrestationEX044) {
            apercuTypePrestation = new ApercuTypePrestation();
            apercuTypePrestation.codeTypePrestation == typePrestationEX044.code;
            apercuTypePrestation.libelleTypePrestation == typePrestationEX044.libelle;
        }

        console.log("A = " + typePrestationEX044.code);
        console.log("B = " + apercuTypePrestation.libelleTypePrestation);

        return apercuTypePrestation;
    }

Unfortunately, it's not working as intended. The console output shows: A = A8C B = undefined

Can anyone help me figure out how to fix this issue?

typescript

Answer №1

Make sure to use = instead of ==. I've updated the code from == to =, and it should work correctly now. 

public getApercuTypePrestationFromTypePrestationEX044(typePrestationEX044: TypePrestationEX044): ApercuTypePrestation {
        let apercuTypePrestation: ApercuTypePrestation;
        if (null != typePrestationEX044) {
            apercuTypePrestation = new ApercuTypePrestation();
            apercuTypePrestation.codeTypePrestation = typePrestationEX044.code;
            apercuTypePrestation.libelleTypePrestation = typePrestationEX044.libelle;
        }

        console.log("A = " + typePrestationEX044.code);
        console.log("B = " + apercuTypePrestation.libelleTypePrestation);

        return apercuTypePrestation;
    }

Remember, in typescript, == or === is for comparisons only, not for assignment. Use = to assign values.

UPDATE

I also noticed that you are checking typePrestationEX044 for null incorrectly.

Replace this: 

if (null != typePrestationEX044) {
            apercuTypePrestation = new ApercuTypePrestation();
            apercuTypePrestation.codeTypePrestation = typePrestationEX044.code;
            apercuTypePrestation.libelleTypePrestation = typePrestationEX044.libelle;
        }

With This

if (typePrestationEX044) {
            apercuTypePrestation = new ApercuTypePrestation();
            apercuTypePrestation.codeTypePrestation = typePrestationEX044.code;
            apercuTypePrestation.libelleTypePrestation = typePrestationEX044.libelle;
        }

This if condition will handle undefined, null, or boolean values automatically.

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