## Remix Debug`
[](https://www.npmjs.com/package/@remix-project/remix-debug)
[](https://www.npmjs.com/package/@remix-project/remix-debug)
[](https://www.npmjs.com/package/@remix-project/remix-debug)
[](https://github.com/ethereum/remix-project/tree/master/libs/remix-debug)
[](https://github.com/ethereum/remix-project/issues)
`@remix-project/remix-debug` is a tool to debug Ethereum transactions on different Remix environments (VM, testnet etc.). It works underneath Remix IDE "DEBUGGER" plugin which is used to analyse step-to-step execution of a transaction to debug it.
### Installation
`@remix-project/remix-debug` is an NPM package and can be installed using NPM as:
`yarn add @remix-project/remix-debug`
### How to use
`@remix-project/remix-debug` can be used as:
```ts
var Debugger = require('remix-debug').EthDebugger
var BreakpointManager = require('remix-debug').BreakpointManager
var debugger = new Debugger({
compilationResult: () => {
return compilationResult // that helps resolving source location
}
})
debugger.addProvider(web3, 'web3')
debugger.switchProvider('web3')
var breakPointManager = new remixCore.code.BreakpointManager(this.debugger, (sourceLocation) => {
// return offsetToLineColumn
})
debugger.setBreakpointManager(breakPointManager)
breakPointManager.add({fileName, row})
breakPointManager.add({fileName, row})
debugger.debug(< tx_hash > )
// this.traceManager.getCurrentCalledAddressAt
debugger.event.register('newTraceLoaded', () => {
// start doing basic stuff like retrieving step details
debugger.traceManager.getCallStackAt(34, (error, callstack) => {})
})
debugger.callTree.register('callTreeReady', () => {
// start doing more complex stuff like resolvng local variables
breakPointManager.jumpNextBreakpoint(true)
var storageView = debugger.storageViewAt(38, < contract address > ,
storageView.storageSlot(0, (error, storage) => {})
storageView.storageRange(error, storage) => {}) // retrieve 0 => 1000 slots
debugger.extractStateAt(23, (error, state) => {
debugger.decodeStateAt(23, state, (error, decodedState) => {})
})
debugger.sourceLocationFromVMTraceIndex(< contract address > , 23, (error, location) => {
debugger.decodeLocalsAt(23, location, (error, decodedlocals) => {})
})
debugger.extractLocalsAt(23, (null, locals) => {})
})
```
It exports:
```javascript
{
init,
traceHelper,
sourceMappingDecoder,
EthDebugger,
TransactionDebugger,
BreakpointManager,
SolidityDecoder,
storage: {
StorageViewer: StorageViewer,
StorageResolver: StorageResolver
},
CmdLine
}
```
Some of the class details are as:
- - - -
**BreakpointManager**
`constructor({ traceManager, callTree, solidityProxy, locationToRowConverter })` : create new instance
`jumpNextBreakpoint(defaultToLimit)` : start looking for the next breakpoint
`jumpPreviousBreakpoint(defaultToLimit)` : start looking for the previous breakpoint
`jump(direction, defaultToLimit)` : start looking for the previous or next breakpoint
`hasBreakpointAtLine((fileIndex, line)` : check the given pair fileIndex/line against registered breakpoints
`hasBreakpoint()` : return true if current manager has breakpoint
`add(sourceLocation)` : add a new breakpoint to the manager
`remove(sourceLocation)` : remove a breakpoint from the manager
- - - -
**StorageViewer**
`constructor (_context, _storageResolver, _traceManager)` : create new instance
`storageRange(defaultToLimit)` : return the storage for the current context (address and vm trace index)
`storageSlot(defaultToLimit)` : return a slot value for the current context (address and vm trace index)
`isComplete(direction, defaultToLimit)` : return True if the storage at @arg address is complete
`initialMappingsLocation((fileIndex, line)` : return all the possible mappings locations for the current context (cached) do not return state changes during the current transaction
`mappingsLocation()` : return all the possible mappings locations for the current context (cached) and current mapping slot. returns state changes during the current transaction
`extractMappingsLocationChanges(sourceLocation)` : retrieve mapping location changes from the storage changes.
- - - -
**StorageResolver**
`constructor (options)` : create new instance
`storageRange(tx, stepIndex, address, callback)` : return the storage for the current context (address and vm trace index)
`initialPreimagesMappings(tx, stepIndex, address, callback)` : return a slot value for the current context (address and vm trace index)
`storageSlot(slot, tx, stepIndex, address, callback)` : return True if the storage at @arg address is complete
`isComplete(address)` : return all the possible mappings locations for the current context (cached) do not return state changes during the current transaction
### Contribute
Please feel free to open an issue or a pull request.
In case you want to add some code, do have a look at our contribution guidelines [here ](https://github.com/ethereum/remix-project/blob/master/CONTRIBUTING.md ). Reach us on [Gitter ](https://gitter.im/ethereum/remix ) in case of any queries.
### License
MIT © 2018-21 Remix Team
