@graphprotocol/graph-cli/src/scaffold/mapping.js

CLI for building for and deploying to The Graph

const path = require('path')

const util = require('../codegen/util')

const generateFieldAssignment = path =>
  `entity.${path.join('_')} = event.params.${path.join('.')}`

const generateFieldAssignments = ({ index, input }) =>
  input.type === 'tuple'
    ? util
        .unrollTuple({ value: input, index, path: [input.name || `param${index}`] })
        .map(({ path }) => generateFieldAssignment(path))
    : generateFieldAssignment([input.name || `param${index}`])

const generateEventFieldAssignments = event =>
  event.inputs.reduce(
    (acc, input, index) => acc.concat(generateFieldAssignments({ input, index })),
    [],
  )

const generateEventIndexingHandlers = (events, contractName) =>
  `
  import { ${events.map(
    event => `${event._alias} as ${event._alias}Event`,
  )}} from '../generated/${contractName}/${contractName}'
  import { ${events.map(event => event._alias)} } from '../generated/schema'

  ${events
    .map(
      event =>
        `
  export function handle${event._alias}(event: ${event._alias}Event): void {
    let entity = new ${
      event._alias
    }(event.transaction.hash.concatI32(event.logIndex.toI32()))
    ${generateEventFieldAssignments(event).join('\n')}

    entity.blockNumber = event.block.number
    entity.blockTimestamp = event.block.timestamp
    entity.transactionHash = event.transaction.hash

    entity.save()
  }
    `,
    )
    .join('\n')}
`

module.exports = {
  generateFieldAssignment,
  generateFieldAssignments,
  generateEventFieldAssignments,
  generateEventIndexingHandlers,
}