Environment variables

Environment variables are names and values you set in Settings → Running → Environment variables. JSpark passes them to every Node Run as process.env, and to a page’s server. Your Snippet reads the name, so the value itself is never in your code, the Library or an export.

Add a variable

1. Open Settings with ⌘, or Ctrl+, and click Running.
2. Under Environment variables, type a Name, such as API_KEY.
3. Type its Value.
4. Click Add, or press ↵ or Enter in the Value field.

The name joins the list above the fields, with its value shown as dots. The next Node Run has it.

• A name is letters, digits and _, and doesn’t start with a digit: API_KEY and token_2 work, 2FA and MY-KEY don’t. Settings says so when a name can’t be used.
• A value can be up to 32 KB. A longer one is refused with That value is too long.

Change or remove one

• To change a value, type the name again and the new value. The button says Replace. A saved value is never shown again, so type it in full.
• To remove a variable, click the trash button beside its name.

Use it in a Snippet

Read the variable by its name:

const key = process.env.API_KEY
const res = await fetch('https://api.example.com/items', {
  headers: { Authorization: `Bearer ${key}` },
})

• Every Node Run gets the variables: Run, Run as you type and the Timeline. A change applies from the next Run.
• A page’s server gets them too. Its port, process.env.PORT, is always the one JSpark chose, even if you set a variable named PORT. See A page with a server.
• Reading process.env doesn’t pause Run as you type. Writing to it does, and so does what you do with the value: the fetch above waits for you to press Run. See Outside Access.

Where the values are kept

• On this computer, in JSpark’s data folder, in a file of their own, apart from your settings.
• Never in your Snippets, the Library or an export, and never in Copy Diagnostics or a problem report.
• Once saved, a value is not shown again. Settings only ever gets the names.
• Restore defaults… leaves them as they are. See Reset or remove JSpark.
• They don’t move with an export. On a new computer, add them again.

More than 3 variables JSpark+

JSpark keeps up to 3 variables. JSpark+ keeps as many as you need. With 3 saved in JSpark, Add wears the JSpark+ mark, and clicking it says that more than 3 environment variables needs JSpark+.

Changing or removing one of the 3 works in JSpark. If a Yearly key lapses, every variable you have stays, is still passed to Runs and can still be changed. Only adding another asks for JSpark+.

Load a .env file JSpark+

In JSpark+, a .env file in the Working Folder is passed to every Node Run too. When a name is in both, the .env value wins over the one in Settings.

# One variable per line
API_KEY=sk-123
export GREETING="Hello\nworld"

• One NAME=value per line. Blank lines and lines starting with # are skipped, and export in front is allowed. A value can be in quotes; in double quotes, \n is a new line.
• JSpark reads the file at every Run, so an edit applies to the next one.
• It is always the Working Folder’s .env, also for a Snippet you set to a folder of your own.
• When JSpark+ finds the file, Settings says The Working Folder’s .env is passed to Runs too, and wins over these.
• Empty… in Settings deletes the .env with every other file in the Working Folder.

In JSpark, the .env is not read, and Settings says JSpark+ also passes the Working Folder’s .env to Runs. Variables set in Settings work in JSpark too.