枚举到字符串查找对象->没有索引签名

Question

I'm trying to map an enum to a String:

enum Status {
    NEW = "NEW",
    INPROCESSING = "IN PROCESSING",
    DONE = "DONE"
};

const statusToColor: { [key in Status ]: string } = {
    "NEW": "blue",
    "IN PROCESSING": "yellow",
    "DONE": "green"
}

Up to this point everything is fine. But when I try:

EDIT: Seems as I simplified the problem to much, as the actual problem still seems to be somewhere else:

The has no Index error only occurs, when I try to feed "statusToColor" from an Array, like this:

const statusArrayToColors = (statusArray: Status[]): string[] => {
    return statusArray.map(status => statusToColor[status])
}

In this case

statusToColor[status]

has no Index signature according to the compiler.

Answer 1

Your code has a typo. This works for me Version 2.5.0-dev.20170629 :

enum Status {
    NEW = "NEW",
    INPROCESSING = "IN PROCESSING",
    DONE = "DONE"
};

const statusToColor: { [key in Status ]: string } = {
    "NEW": "blue",
    "IN PROCESSING": "yellow",
    "DONE": "green"
}

const color: string = statusToColor[Status.NEW];

Check the line of statusToColor . To define the type you must use colon : , not equal = .

Note: you need at least typescript version 2.4.