Update script

[cliffoo]

Building on top of pull#179

• Instead of setting value to 1, increment (Also renamed run.js to increment.js).
• Added instruction on top (how to run + you should truffle migrate before).
• Added link to docs.
• Added some helpful logging.

Other small things:

• indent = 2
• cb => callback
• Directly export, no main
• Use const

Also currently the try-catch in run.js only catches error if:

• Compiled but not deployed (truffle compile && truffle exec scripts/run.js)

It doesn't catch:

• Not compiled (Just truffle exec scripts/run.js)

It's rather verbose when I try-catch both cases like below, so I thought it's better to just say at the top of the file: You should run truffle migrate

function getSimpleStorage() {
  try {
    return artifacts.require("SimpleStorage");
  } catch (err) {
    throw new Error("Failed to import SimpleStorage contract artifact. You should `truffle migrate` first.");
  }
}

async function getDeployed(contract) {
  try {
    return await contract.deployed();
  } catch (err) {
    throw new Error("Failed to get deployed SimpleStorage instance. You should `truffle migrate` first.");
  }
}

module.exports = async function (callback) {
  const SimpleStorage = getSimpleStorage();
  const deployed = await getDeployed(SimpleStorage);

  const currentValue = (await deployed.read()).toNumber();
  console.log(`Current SimpleStorage value: ${currentValue}`);

  await deployed.write(value + 1);

  const updatedValue = (await deployed.read()).toNumber();
  console.log(`Updated SimpleStorage value: ${updatedValue}`);

  callback();
};