Below is the method I am working with:
public test(keyValue : { [index:string] : string} ){
...
}
I need to modify the signature so that keyValue (an array filled with strings) will have an index of type string. However, I still want to be able to use it as an array containing strings in a way like this (though the syntax might not be correct for using both key and value at once):
keyValue.forEach(key, value => {
//key is string
//value is string
});
Understanding the concept of Typescript index signatures can be a bit tricky at first glance. When you define
keyValue : { [index:string] : string}This means that your prototype will accept any object with string keys and string values, like:
{
"keyOne": "valueOne",
"keyTwo": "valueTwo"
}
To iterate over the key-value pairs in your object, you can use:
for (let [key, value] of Object.entries(keyValue)) {
/* Do something... */
}
Check out this stackblitz example I've prepared to demonstrate this. Keep in mind that while defining an index signature like the one you suggested, it doesn't guarantee that the passed object will match it (no runtime errors will be thrown).
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