refactor(command-utils): fix runCommandAsync

We treated it as something that returns a Promise when it does not. This fixes it by wrapping it in
a Promise
TEST PLAN:
Change some command temporarly (e.g. ui-scripts tag) so it uses RunCommandAsync and output its
return value

packages/command-utils/lib/index.js

@@ -106,14 +106,48 @@ function runCommandSync(bin, args = [], envVars = {}, opts = {}) {
  return result
 }
 
+/**
+ * Runs the given command asynchronously, returns a Promise that contains its
+ * stdout and stderr as strings
+ * @param bin path to the binary
+ * @param args arguments in an array
+ * @param envVars environment vars as key-value pairs
+ * @param opts Options to `childProcess.spawn`
+ * @returns {Promise<{stdout: string, stderr: string}>}
+ */
 async function runCommandAsync(bin, args = [], envVars = {}, opts = {}) {
  const result = crossSpawn.spawn(bin, args, {
  env: { ...process.env, ...envVars },
  stdio: 'inherit',
  windowsHide: true,
  ...opts
  })
- return result
+ let stdout = ''
+ let stderr = ''
+ if (result.stdout) {
+ result.stdout.on('data', (data) => {
+ stdout += data.toString()
+ })
+ }
+ if (result.stderr) {
+ result.stderr.on('data', (data) => {
+ stderr += data.toString()
+ })
+ }
+ const promise = new Promise((resolve, reject) => {
+ result.on('error', reject)
+
+ result.on('close', (code) => {
+ if (code === 0) {
+ resolve({ stdout: stdout, stderr: stderr })
+ } else {
+ error(`child process ${bin} ${args} exited with code ${code}`)
+ reject({ stdout: stdout, stderr: stderr })
+ }
+ })
+ })
+ promise.child = result
+ return promise
 }
 
 function resolveBin(

packages/command-utils/package.json

@@ -12,7 +12,8 @@
  "bugs": "https:/instructure/instructure-ui/issues",
  "scripts": {
  "lint": "run -T ui-scripts lint",
- "lint:fix": "run -T ui-scripts lint --fix"
+ "lint:fix": "run -T ui-scripts lint --fix",
+ "build:types": "run -T tsc -p tsconfig.build.json"
  },
  "license": "MIT",
  "dependencies": {