token-withdraw

Tutorial: token withdraw

token-withdraw shows how to move ERC-20 tokens from a chain to its parent chain (e.g. from Arbitrum to Ethereum).

Note that this repo covers initiating a token withdrawal; for a demo on releasing the funds from the Outbox, see outbox-execute

How it works (under the hood)

To withdraw a token from an Arbitrum chain, a message is send from a gateway contract which burns the token on the origin chain, and sends a message to its parent chain, which allow the token to be released from escrow once the dispute period is expired.

For more info, see child-to-parent messages.

Standard ERC-20 withdrawal

In this tutorial, we deploy a fresh token and then deposit some to the child chain. Then, we use these new tokens to trigger a withdrawal back to the parent chain.

We use our Arbitrum SDK library for the token bridge interactions.

See ./exec.js for inline explanation.

Set environment variables

Set the values shown in .env-sample as environmental variables. To copy it into a .env file:

cp .env-sample .env

You'll still need to edit some variables, i.e., PRIVATE_KEY, CHAIN_RPC and PARENT_CHAIN_RPC.

Note that you can also set the environment variables in an .env file in the root of the monorepo, which will be available in all tutorials.

Run

yarn run token-withdraw