理解“无阴影变量" tslint警告 [英] Making Sense of 'No Shadowed Variable' tslint Warning

问题描述

我有一个功能，可以根据传入的特定规则检查顺序流中的当前阶段，并根据该值在我的Angular 2应用程序中分配下一个值.看起来像这样:

I have a function that checks for the current stage in a sequential stream, based on a particular discipline that is passed in, and, according to that value, assigns the next value in my Angular 2 app. It looks something like this:

private getNextStageStep(currentDisciplineSelected) {
    const nextStageStep = '';
        if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 1') {
            const nextStageStep = 'step 2';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 2') {
            const nextStageStep = 'step 3';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 3') {
            const nextStageStep = 'step 4';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 4') {
            const nextStageStep = 'step 5';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 5') {
            const nextStageStep = 'step 6';
    }
    return nextStageStep;
}

我在这里做的是返回"nextStageStep"的值，因为这是为了使正确的舞台步骤发生而我要传递的内容.

What I'm doing here is returning the value of "nextStageStep", because that's what I'll be then passing in order for the correct stage step to happen.

现在，我的tslint用无阴影变量"警告强调每个"nextStageStep"变量的出现.如果我删除初始化为空字符串的行，警告就会消失，但随后出现错误，"Return statement"中将显示"Cannot find nextStageStep".

Right now, my tslint is underlining each of the "nextStageStep" variable occurrences with the warning "no shadowed variables". If I remove the line where I initialize to an empty string that warning goes away, but then I get the error, "Cannot find nextStageStep" showing up in my return statement.

原始阴影变量警告有什么问题，有没有替代的写法，和/或在这种情况下我是否应该忽略tslint警告?

What is the issue with the original shadowed variable warning, and is there an alternative way to write this, and/or should I simply ignore the tslint warning in this situation?

推荐答案

lint抱怨，因为您多次重新定义了相同的变量.因此，替换包含它的封闭中的那些.

The linter complains because you are redefining the same variable multiple times. Thus replacing the ones in the closure containing it.

代替重新声明它，只需使用它即可:

Instead of redeclaring it just use it:

private getNextStageStep(currentDisciplineSelected) {
    let nextStageStep = '';
        if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 1') {
             nextStageStep = 'step 2';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 2') {
             nextStageStep = 'step 3';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 3') {
             nextStageStep = 'step 4';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 4') {
             nextStageStep = 'step 5';
        } else if (this.stageForDiscipline(this.currentDisciplineSelected) === 'step 5') {
             nextStageStep = 'step 6';
    }
    return nextStageStep;
}

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