💪 Use unknownutil functions internally

Author: lambdalisue

denops_std/buffer/buffer.ts

@@ -1,4 +1,5 @@
 import type { Denops } from "https://deno.land/x/denops_core@v5.0.0/mod.ts";
+import { maybe } from "https://deno.land/x/unknownutil@v3.10.0/mod.ts#^";
 import * as autocmd from "../autocmd/mod.ts";
 import * as batch from "../batch/mod.ts";
 import * as fn from "../function/mod.ts";
@@ -7,7 +8,7 @@ import { execute } from "../helper/mod.ts";
 import {
   FileFormat,
   findFileFormat,
-  maybeFileFormat,
+  isFileFormat,
   splitText,
 } from "./fileformat.ts";
 import { tryDecode } from "./fileencoding.ts";
@@ -284,7 +285,7 @@ export async function decode(
   } else {
     [enc, text] = tryDecode(data, fileencodings);
   }
-  const ff = maybeFileFormat(options.fileformat) ??
+  const ff = maybe(options.fileformat, isFileFormat) ??
     findFileFormat(text, fileformats) ?? fileformat;
   return {
     content: splitText(text, ff),

denops_std/buffer/fileformat.ts

@@ -1,35 +1,30 @@
-import { is } from "https://deno.land/x/unknownutil@v3.10.0/mod.ts#^";
+import {
+  assert,
+  ensure,
+  is,
+  maybe,
+  PredicateType,
+} from "https://deno.land/x/unknownutil@v3.10.0/mod.ts#^";
 
-export type FileFormat = "unix" | "dos" | "mac";
+export const isFileFormat = is.LiteralOneOf(["unix", "dos", "mac"] as const);
+
+export type FileFormat = PredicateType<typeof isFileFormat>;
+
+export const assertFileFormat = (v: unknown): asserts v is FileFormat =>
+  assert(v, isFileFormat);
+
+export const ensureFileFormat = (v: unknown): FileFormat =>
+  ensure(v, isFileFormat);
+
+export const maybeFileFormat = (v: unknown): FileFormat | undefined =>
+  maybe(v, isFileFormat);
 
 const fileFormatDelimiters = {
   unix: "\n",
   dos: "\r\n",
   mac: "\r",
 };
 
-export function isFileFormat(v: unknown): v is FileFormat {
-  return is.String(v) && v in fileFormatDelimiters;
-}
-
-export function assertFileFormat(v: unknown): asserts v is FileFormat {
-  if (!isFileFormat(v)) {
-    throw new Error(`Unknown fileformat '${v}' is specified`);
-  }
-}
-
-export function ensureFileFormat(v: unknown): FileFormat {
-  assertFileFormat(v);
-  return v;
-}
-
-export function maybeFileFormat(v: unknown): FileFormat | undefined {
-  if (isFileFormat(v)) {
-    return v;
-  }
-  return undefined;
-}
-
 /**
  * Split text as Text File in POSIX.
  */