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typescript - 访问块外的变量

问题描述

我是 TypeScript 的初学者（很明显，我来自 java 世界）。我目前正在尝试做一个这样的映射器：

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;
    }

但这显然不起作用：在控制台中，我有： A = A8C B = undefined

我该如何解决？

标签： typescript

解决方案

您正在使用==而不是=. 我已经更改==为=，它现在应该可以工作了。

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;
    }

在打字稿中， ==或===用于比较而不是分配，以便分配您必须使用的值=

更新

我还注意到您typePrestationEX044以错误的方式检查 null 。

改变这个：

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

至此

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

此if条件将自动检查undefined,null或boolean

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