refactor for cross platform use

src/github.ts

@@ -0,0 +1,86 @@
+import { GitHub } from '@actions/github';
+import { Config } from './util';
+import { lstatSync, readFileSync } from 'fs';
+import { getType } from 'mime';
+import { basename } from 'path';
+
+export interface ReleaseAsset {
+  name: string,
+  mime: string,
+  size: number,
+  file: Buffer
+}
+
+export interface Release {
+	upload_url: string,
+	html_url: string
+}
+
+export const asset = (path: string): ReleaseAsset => {
+  return {
+    name: basename(path),
+    mime: mimeOrDefault(path),
+    size: lstatSync(path).size,
+    file: readFileSync(path)
+  };
+}
+
+export const mimeOrDefault = (path: string): string => {
+  return getType(path) || "application/octet-stream";
+}
+
+export const upload = async (
+  gh: GitHub,
+  url: string,
+  path: string
+): Promise<any> => {
+  let {
+    name,
+    size,
+    mime,
+    file
+  } = asset(path);
+  console.log(`⬆️ Uploading ${name}...`);
+  return await gh.repos.uploadReleaseAsset({
+    url,
+    headers:  {
+      "content-length": size,
+      "content-type": mime
+    },
+    name,
+    file
+  });
+}
+
+export const release = async (
+  config: Config,
+  gh: GitHub
+): Promise<Release> => {
+  let [owner, repo] = config.github_repository.split("/");
+  try {
+    let release = await gh.repos.getReleaseByTag({
+      owner,
+      repo,
+      tag: config.github_ref
+    });
+    return release.data;
+  } catch (error) {
+    if (error.status === 404) {
+      const tag_name = config.github_ref.replace("refs/tags/", "");
+      const name = config.input_name || tag_name;
+      const body = config.input_body;
+      const draft = config.input_draft;
+      let release = await gh.repos.createRelease({
+        owner,
+        repo,
+        tag_name,
+        name,
+        body,
+        draft
+      });
+      return release.data;
+    } else {
+      throw error;
+    }
+  }
+}