38 lines
901 B
TypeScript
38 lines
901 B
TypeScript
import { pipe } from "./composition.ts";
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/**
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* Get a function to check that inputs are instances of a given type
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*/
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export function isinstance<T, S extends T>(
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ref: { new (...args: any[]): T },
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): (input: S) => input is Extract<T, S> {
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return (x): x is Extract<T, S> => x instanceof ref;
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}
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/**
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* Check that a value is not null, throwing an error if it is
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*/
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export function nn<T>(value: T | null): T {
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if (value === null) {
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throw new Error("null value");
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} else {
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return value;
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}
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}
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/**
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* Check that a value is not undefined, throwing an error if it is
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*/
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export function nu<T>(value: T | undefined): T {
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if (typeof value === "undefined") {
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throw new Error("undefined value");
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} else {
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return value;
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}
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}
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/**
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* Check that a value is not null nor undefined, throwing an error if it is
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*/
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export const nnu: <T>(value: T | null | undefined) => T = pipe(nn, nu);
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