labelKeyResolverSample.ts

labelKeyResolverSample.ts

import * as strings from 'myStrings';

const getLocalizedStringKey: (keyResolver: (() => string)) => string = (nameResolver: () => string) => {

    console.log("getLocalizedStringKey() - name resolver: ", nameResolver);
    const dotFormNamePattern = /function\s*\(\)\s*\{\s*return (.*)\.(.*)\s*\}/;
    const dotFormNameMatch = dotFormNamePattern.exec(nameResolver + '');

    let labelKey: string = null;
    if (dotFormNameMatch == null) {
        const arrayIndexingFormNamePattern = /return (.*)\[\"(.*)\"\]/;
        const arrayIndexingFormNameMatch = arrayIndexingFormNamePattern.exec(nameResolver + '');
        console.log("getLocalizedStringKey() - uses array indexing form");
        if (arrayIndexingFormNameMatch == null) {
            throw new Error("The keyResolver is invalid. Make sure to use '() => strings.LabelKey'");
        }

        labelKey = arrayIndexingFormNameMatch[2];
    } else {
        console.log("getLocalizedStringKey() - uses dot form");
        labelKey = dotFormNameMatch[2];
    }

    return labelKey;
};

const getKey = (labelKey: string | (() => string)) => {
    let key: string = null;
    if (!labelKey) {
        throw new Error('The labelKey argument is not set');
    }

    if (typeof labelKey === 'string') {
        key = labelKey as string;
    } else if (typeof labelKey === 'function') {
        key = getLocalizedStringKey(labelKey as (() => string));
    } else {
        key = (labelKey as any).toString();
    }

    return key;
};

export const doStuff = (labelKey: string | (() => string)) => {
    const effectiveKey = getKey(labelKey);
    // Do stuff with key here ...
};

// I can than use
doStuff(() => strings.MyKey);           // <= Compilation will succeed
//doStuff(() => strings.MyKy);          // <= Compilation would fail

// instead of
doStuff("MyKey");                       // <= Compilation will succeed and code will work fine
doStuff("Myky");                        // <= Compilation will succeed and code won't work as expected