mentsu-gene-chain-splicer

A JavaScript utility for dynamically extending object instances by splicing methods into their prototype chain.

Installation

Prerequisites

• Node.js >= 20.0.0
• npm >= 10.0.0

Setting up .npmrc

This package is published to GitHub Packages. Create a .npmrc file in your project root:

@openreachtech:registry=https://npm.pkg.github.com

Install

npm install @openreachtech/mentsu-gene-chain-splicer

Usage

Import the module:

import {
  GeneChainSplicer,
} from '@openreachtech/mentsu-gene-chain-splicer'

(1) Basic Example

Override a single method:

class AlphaCore {
  firstValue () {
    return 1000
  }
}

const alphaCore = new AlphaCore()

const splicer = GeneChainSplicer.create({
  core: alphaCore,
})

splicer.spliceGene({
  mixin: {
    firstValue () {
      return 1999
    },
  },
})

console.log(alphaCore.firstValue()) // 1999

(2) Multiple Members

Override multiple members at once:

class BetaCore {
  firstValue () {
    return 2000
  }

  secondValue () {
    return 3000
  }
}

const betaCore = new BetaCore()

const splicer = GeneChainSplicer.create({
  core: betaCore,
})

splicer.spliceGene({
  mixin: {
    firstValue () {
      return 2999
    },

    secondValue () {
      return 3999
    },
  },
})

console.log(betaCore.firstValue()) // 2999
console.log(betaCore.secondValue()) // 3999

(3) Method Chaining

Chain multiple spliceGene() calls:

class GammaCore {
  firstValue () {
    return 4000
  }

  secondValue () {
    return 5000
  }
}

const gammaCore = new GammaCore()

const splicer = GeneChainSplicer.create({
  core: gammaCore,
})

splicer
  .spliceGene({
    mixin: {
      firstValue () {
        return 4999
      },
    },
  })
  .spliceGene({
    mixin: {
      secondValue () {
        return 5999
      },
    },
  })

console.log(gammaCore.firstValue()) // 4999
console.log(gammaCore.secondValue()) // 5999

(4) Splice Order

Later splices take precedence over earlier ones:

class DeltaCore {
  firstValue () {
    return 6000
  }
}

const deltaCore = new DeltaCore()

const splicer = GeneChainSplicer.create({
  core: deltaCore,
})

splicer
  .spliceGene({
    mixin: {
      firstValue () {
        return 6999
      },
    },
  })
  .spliceGene({
    mixin: {
      firstValue () {
        return 6888
      },
    },
  })

console.log(deltaCore.firstValue()) // 6888

Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Run tests and linting
5. Submit a pull request

git clone https://github.com/openreachtech/mentsu-gene-chain-splicer.git
cd mentsu-gene-chain-splicer
npm install
npm run lint
npm test

License

This project is released under the MIT License.

For more details, please see in the LICENSE file.

Developer

Open Reach Tech Inc.

Copyright

© 2026 Open Reach Tech Inc.