Convert ABI to solidity file

abi-to-sol.js

/**
 * Convert ABI json file to solidity interface contract
 */

const fs = require('fs');
const args = process.argv.slice(2);


function convert(inputFilename) {
    const abi = JSON.parse(fs.readFileSync(inputFilename, 'utf8'));
    const name = inputFilename.match(/(\w+)/)[1]
    const w = process.stdout.write.bind(process.stdout);

    w(`pragma solidity >=0.4.21 <0.6.0;\n`)
    w(`// converted from ${inputFilename}\n`);
    w(`contract ${name} {\n\n`)

    abi.forEach(f => {
        if (f.type === "constructor") return;
        w(`    ${f.type}${f.name?" "+f.name:""}`);

        if (f.inputs && f.inputs.length) {
            w("(\n");
            w(f.inputs.map(i => `        ${i.type} ${["string"].indexOf(i.type)>=0?" calldata ":""}${i.name}`).join(",\n"));
            w("\n    )");
        } else {
            w("()");
        }

        if (["function"].indexOf(f.type) >= 0) {
            w(" external");
        }
        w(`${f.view ? " view" : ""}${f.payable?" payable":""}`)

        if (f.outputs && f.outputs.length){
            w(" returns (\n");
            w(f.outputs.map(o => `        ${o.type}${["string"].indexOf(o.type)>=0?" memory":""}${o.name ? " "+o.name:""}`).join(",\n"));
            w("\n    )");
        }

        w(";\n\n");
    })
    w("}\n")
}

args.forEach(convert)