How to read a List from a data source context?

[PaulRBerg]

The docs mention the possibility of defining an item of type List in the YAML subgraph manifest:

dataSources:
  - kind: ethereum/contract
    name: ContractName
    network: mainnet
    context:
      list_example:
        type: List
        data:
          - type: "BigInt"
            data: "1"
          - type: "BigInt
            data: "2"
          - type: "BigInt"
            data: "3"

But there is no guidance provided for how to read that list in an AssemblyScript mapping.

I wrote it like this but I'm not sure if it's correct:

export function getStringArray(key: string): string[] {
  const context = dataSource.context();
  const value = context.get("list_example");
  return value!.toStringArray();
}

Can anyone from Edge & Node please confirm this?

[shiyasmohd]

@PaulRBerg here is an example to use list datasource context

export function getStringArray(key: string): string[] {
  const context = dataSource.context();
  const value = context.get("list_example");
  return value.map<string>(item => item.toBigInt().toString());;
}

[PaulRBerg]

Thank you!!

[PaulRBerg]

@shiyasmohd the code you provided doesn't work

> Property 'map' does not exist on type 'Value'.ts(2339)
> Parameter 'item' implicitly has an 'any' type.ts(7006)

using @graphprotocol/graph-ts v0.38.1

[shiyasmohd]

Small correction. Corrected Code.

export function getStringArray(key: string): string[] {
  const context = dataSource.context();
  const value = context.get("list_example")?.toArray();
  return value!.map<string>(item => item.toBigInt().toString());;
}