1 files changed, 80 insertions, 0 deletions
diff --git a/std/encoding/_yaml/utils.ts b/std/encoding/_yaml/utils.ts
new file mode 100644
index 000000000..4630a45a2
--- /dev/null
+++ b/std/encoding/_yaml/utils.ts
@@ -0,0 +1,80 @@
+// Ported from js-yaml v3.13.1:
+// https://github.com/nodeca/js-yaml/commit/665aadda42349dcae869f12040d9b10ef18d12da
+// Copyright 2011-2015 by Vitaly Puzrin. All rights reserved. MIT license.
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+/* eslint-disable-next-line @typescript-eslint/no-explicit-any */
+export type Any = any;
+
+export function isNothing(subject: unknown): subject is never {
+  return typeof subject === "undefined" || subject === null;
+}
+
+export function isArray(value: unknown): value is Any[] {
+  return Array.isArray(value);
+}
+
+export function isBoolean(value: unknown): value is boolean {
+  return typeof value === "boolean" || value instanceof Boolean;
+}
+
+export function isNull(value: unknown): value is null {
+  return value === null;
+}
+
+export function isNumber(value: unknown): value is number {
+  return typeof value === "number" || value instanceof Number;
+}
+
+export function isString(value: unknown): value is string {
+  return typeof value === "string" || value instanceof String;
+}
+
+export function isSymbol(value: unknown): value is symbol {
+  return typeof value === "symbol";
+}
+
+export function isUndefined(value: unknown): value is undefined {
+  return value === undefined;
+}
+
+export function isObject(value: unknown): value is object {
+  return value !== null && typeof value === "object";
+}
+
+export function isError(e: unknown): boolean {
+  return e instanceof Error;
+}
+
+export function isFunction(value: unknown): value is () => void {
+  return typeof value === "function";
+}
+
+export function isRegExp(value: unknown): value is RegExp {
+  return value instanceof RegExp;
+}
+
+export function toArray<T>(sequence: T): T | [] | [T] {
+  if (isArray(sequence)) return sequence;
+  if (isNothing(sequence)) return [];
+
+  return [sequence];
+}
+
+export function repeat(str: string, count: number): string {
+  let result = "";
+
+  for (let cycle = 0; cycle < count; cycle++) {
+    result += str;
+  }
+
+  return result;
+}
+
+export function isNegativeZero(i: number): boolean {
+  return i === 0 && Number.NEGATIVE_INFINITY === 1 / i;
+}
+
+export interface ArrayObject<T = Any> {
+  [P: string]: T;
+}