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import * as ethUtil from 'ethereumjs-util';
import * as request from 'request-promise-native';
import { constants } from './constants';
export class RPC {
private _url: string;
private _id: number;
constructor() {
this._url = constants.RPC_URL;
this._id = 0;
}
public async takeSnapshotAsync(): Promise<number> {
const method = 'evm_snapshot';
const params: any[] = [];
const payload = this._toPayload(method, params);
const snapshotIdHex = await this._sendAsync(payload);
const snapshotId = ethUtil.bufferToInt(ethUtil.toBuffer(snapshotIdHex));
return snapshotId;
}
public async revertSnapshotAsync(snapshotId: number): Promise<boolean> {
const method = 'evm_revert';
const params = [snapshotId];
const payload = this._toPayload(method, params);
const didRevert = await this._sendAsync(payload);
return didRevert;
}
public async increaseTimeAsync(time: number) {
const method = 'evm_increaseTime';
const params = [time];
const payload = this._toPayload(method, params);
return this._sendAsync(payload);
}
public async mineBlockAsync(): Promise<void> {
const method = 'evm_mine';
const params: any[] = [];
const payload = this._toPayload(method, params);
await this._sendAsync(payload);
}
private _toPayload(method: string, params: any[] = []): string {
const payload = JSON.stringify({
id: this._id,
method,
params,
});
this._id += 1;
return payload;
}
private async _sendAsync(payload: string): Promise<any> {
const opts = {
method: 'POST',
uri: this._url,
body: payload,
headers: {
'content-type': 'application/json',
},
};
const bodyString = await request(opts);
const body = JSON.parse(bodyString);
return body.result;
}
}
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