@positron/ts-utils@0.1.0

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export const isNonNull = <T>(value: T): value is NonNullable<T> =>
  value !== null && value !== undefined;

export const isObject = (value: unknown): value is object =>
  typeof value === 'object' && value !== null;

export const isFunction = (value: unknown): value is Function =>
  typeof value === 'function';

export const isString = (value: unknown): value is string =>
  typeof value === 'string';

export const isNumber = (value: unknown): value is number =>
  typeof value === 'number';

export const isArrayOf = <T>(
  value: unknown,
  predicate: (value: unknown) => value is T
): value is T[] => Array.isArray(value) && value.every(predicate);

export const isObjectOf = <T, Original extends object>(
  value: Original,
  predicate: (value: unknown) => value is T
): value is Original & { [key: string]: T } =>
  isObject(value) && Object.values(value).every(predicate);

export const isArrayElement = <T>(
  value: unknown,
  array: readonly T[]
): value is T => array.includes(value as T);

export const isOptional = <T>(
  value: unknown,
  predicate: (v: unknown) => v is T
): value is T | undefined => value === undefined || predicate(value);

export const hasProperty = <T extends object, K extends string, V>(
  value: T,
  key: K,
  predicate: (value: unknown) => value is V
): value is T & { [key in K]: V } =>
  key in value && predicate((value as { [key in K]: V })[key]);

export function assert<T>(
  value: unknown,
  predicate: (v: unknown) => v is T
): asserts value is T {
  if (!predicate(value)) throw new Error('Invalid value');
}

export function assertHasProperty<T extends object, K extends string, V>(
  value: T,
  key: K,
  predicate: (v: unknown) => v is V
): asserts value is T & { [key in K]: V } {
  if (!hasProperty(value, key, predicate))
    throw new Error(`Invalid value for property key ${String(key)}`);
}