saveKeypairSignerToEnvFile

function saveKeypairSignerToEnvFile(
   keypairSigner, 
   variableName, 
envFilePath): Promise<void>;

Save an extractable KeyPairSigner to a filesystem wallet json file (i.e. same format as those generated by the solana-keygen command)

Parameters

Parameter	Type	Default value	Description
`keypairSigner`	`KeyPairSigner`	`undefined`	an extractable `KeyPairSigner`
`variableName`	`string`	`undefined`	environment variable name accessible via `process.env[variableName]` after env file is loaded
`envFilePath`	`string`	`".env"`	environment variable file path, default = `.env` in the current working directory

Promise<void>