typir/src/utils/utils.ts

General purpose type checking library

/******************************************************************************
 * Copyright 2024 TypeFox GmbH
 * This program and the accompanying materials are made available under the
 * terms of the MIT License, which is available in the project root.
 ******************************************************************************/

import { Type } from '../graph/type-node.js';
import { Kind } from '../kinds/kind.js';

export function assertTrue(condition: boolean, msg?: string): asserts condition {
    if (!condition) {
        throw new Error(msg);
    }
}

export function toArray<T>(value: undefined | T | T[], options?: { newArray: boolean }): T[] {
    if (value === undefined) {
        return [];
    }
    if (Array.isArray(value)) {
        if (options?.newArray) {
            return [...value];
        } else {
            return value;
        }
    }
    return [value];
}
export function toArrayWithValue<T>(value: T, array?: undefined | T | T[]): T[] {
    if (array === undefined) {
        return [value];
    }
    if (Array.isArray(array)) {
        array.push(value);
        return array;
    }
    return [array, value];
}

export function removeFromArray<T>(value: T | undefined, array: T[] | undefined): boolean {
    if (value === undefined || array === undefined) {
        return false;
    }
    const index = array.indexOf(value);
    if (index >= 0) {
        array.splice(index, 1);
        return true;
    } else {
        return false;
    }
}

export function assertUnreachable(_: never): never {
    throw new Error('Error! The input value was not handled.');
}

export function assertKind<T extends Kind>(kind: unknown, check: (kind: unknown) => kind is T, msg?: string): asserts kind is T {
    if (check(kind)) {
        // this is the expected case
    } else {
        throw new Error(msg ?? `'${kind}' has another kind`);
    }
}

export function assertTypirType<T extends Type>(type: unknown, check: (type: unknown) => type is T, msg?: string): asserts type is T {
    if (check(type)) {
        // this is the expected case
    } else {
        throw new Error(msg ?? `'${type}' has another type`);
    }
}