ERC20.ts

import { ContractFactory, RequestManager, Contract, Address, TransactionOptions } from 'eth-connect'
import BigNumber from 'bignumber.js'

const ERC20Abi = [
  {
    constant: true,
    inputs: [],
    name: 'name',
    outputs: [
      {
        name: '',
        type: 'string',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    constant: false,
    inputs: [
      {
        name: '_spender',
        type: 'address',
      },
      {
        name: '_value',
        type: 'uint256',
      },
    ],
    name: 'approve',
    outputs: [
      {
        name: '',
        type: 'bool',
      },
    ],
    payable: false,
    stateMutability: 'nonpayable',
    type: 'function',
  },
  {
    constant: true,
    inputs: [],
    name: 'totalSupply',
    outputs: [
      {
        name: '',
        type: 'uint256',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    constant: false,
    inputs: [
      {
        name: '_from',
        type: 'address',
      },
      {
        name: '_to',
        type: 'address',
      },
      {
        name: '_value',
        type: 'uint256',
      },
    ],
    name: 'transferFrom',
    outputs: [
      {
        name: '',
        type: 'bool',
      },
    ],
    payable: false,
    stateMutability: 'nonpayable',
    type: 'function',
  },
  {
    constant: true,
    inputs: [],
    name: 'decimals',
    outputs: [
      {
        name: '',
        type: 'uint8',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    constant: true,
    inputs: [
      {
        name: '_owner',
        type: 'address',
      },
    ],
    name: 'balanceOf',
    outputs: [
      {
        name: 'balance',
        type: 'uint256',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    constant: true,
    inputs: [],
    name: 'symbol',
    outputs: [
      {
        name: '',
        type: 'string',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    constant: false,
    inputs: [
      {
        name: '_to',
        type: 'address',
      },
      {
        name: '_value',
        type: 'uint256',
      },
    ],
    name: 'transfer',
    outputs: [
      {
        name: '',
        type: 'bool',
      },
    ],
    payable: false,
    stateMutability: 'nonpayable',
    type: 'function',
  },
  {
    constant: true,
    inputs: [
      {
        name: '_owner',
        type: 'address',
      },
      {
        name: '_spender',
        type: 'address',
      },
    ],
    name: 'allowance',
    outputs: [
      {
        name: '',
        type: 'uint256',
      },
    ],
    payable: false,
    stateMutability: 'view',
    type: 'function',
  },
  {
    payable: true,
    stateMutability: 'payable',
    type: 'fallback',
  },
  {
    anonymous: false,
    inputs: [
      {
        indexed: true,
        name: 'owner',
        type: 'address',
      },
      {
        indexed: true,
        name: 'spender',
        type: 'address',
      },
      {
        indexed: false,
        name: 'value',
        type: 'uint256',
      },
    ],
    name: 'Approval',
    type: 'event',
  },
  {
    anonymous: false,
    inputs: [
      {
        indexed: true,
        name: 'from',
        type: 'address',
      },
      {
        indexed: true,
        name: 'to',
        type: 'address',
      },
      {
        indexed: false,
        name: 'value',
        type: 'uint256',
      },
    ],
    name: 'Transfer',
    type: 'event',
  },
]

export interface IERC20 extends Contract {
  name(options?: Partial<TransactionOptions>): Promise<string>
  totalSupply(options?: Partial<TransactionOptions>): Promise<BigNumber>
  approve(_spender: Address, _value: BigNumber, options?: Partial<TransactionOptions>): Promise<boolean>
  transferFrom(_from: Address, _to: Address, _value: BigNumber, options?: Partial<TransactionOptions>): Promise<boolean>
  decimals(options?: Partial<TransactionOptions>): Promise<number>
  balanceOf(_of: Address, options?: Partial<TransactionOptions>): Promise<BigNumber>
  symbol(options?: Partial<TransactionOptions>): Promise<string>
  transfer(_to: Address, _value: BigNumber, options?: Partial<TransactionOptions>): Promise<boolean>
  allowance(_owner: Address, _spender: Address, options?: Partial<TransactionOptions>): Promise<BigNumber>
}

// TODO: Cache contracts by address+requestManager, contracts are immutable

export async function getERC20(requestManager: RequestManager, address: Address): Promise<IERC20> {
  return (await new ContractFactory(requestManager, ERC20Abi).at(address)) as IERC20
}