lib/keyed-type.ts

// Copyright (c) 2020, Compiler Explorer Authors
// All rights reserved.
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import {Keyable} from './keyed-type.interfaces';
import {logger} from './logger';

function makeKeyMap<T extends Keyable>(typeName: string, objects: Record<string, T>): Record<string, T> {
    const keyToNameMap: Record<string, string> = {};
    const keyToTypeMap: Record<string, T> = {};
    let haveErrors = false;

    for (const name in objects) {
        const type = objects[name];
        const key = type.key;

        if (key === undefined) {
            logger.error(`${typeName} ${name} does not provide a key value`);
            haveErrors = true;
        } else if (!key) {
            logger.error(`${typeName} ${name} provides empty key value`);
            haveErrors = true;
        } else if (keyToTypeMap[key] === undefined) {
            keyToTypeMap[key] = type;
            keyToNameMap[key] = name;
        } else {
            logger.error(`${typeName} ${name} key conflicts with ${keyToNameMap[key]}`);
            haveErrors = true;
        }
    }

    // If there are any errors, we just log them and continue above. Once done, we throw to
    // halt instance startup so the logs don't get lost in a wall of text.
    if (haveErrors) throw new Error(`${typeName} KeyedType configuration error`);

    return keyToTypeMap;
}

export function makeKeyedTypeGetter<T extends Keyable>(
    typeName: string,
    objects: Record<string, T>,
): (key: string) => T {
    const keyMap = makeKeyMap(typeName, objects);

    return function getFromKey(key) {
        if (key in keyMap) {
            return keyMap[key];
        } else {
            throw new Error(`No ${typeName} named '${key}' found`);
        }
    };
}

export function makeDefaultedKeyedTypeGetter<T extends Keyable>(
    typeName: string,
    objects: Record<string, T>,
    defaultObject: T,
): (key: string) => T {
    const keyMap = makeKeyMap(typeName, objects);

    return function getFromKey(key) {
        if (key in keyMap) {
            return keyMap[key];
        } else {
            return defaultObject;
        }
    };
}