putout-new-line-plugin.js

module.exports.fix = (path) => {
  path.node.value.raw = '\n';
};

module.exports.traverse = ({push}) => ({
  TemplateLiteral(path) {
    const [start] = path.node.quasis;
    
    if (/^\n\s+/.test(start.value.raw))
      push(path.get('quasis.0'));
  }
});

source.js

export function set(extra) {
  extra += `
${prefix}${casing[field] || field}
${value.raw ? "=" : ":"} 
${value.value}`;
  return extra;
}

trace.js

const fs = require('fs')
const putout = require('putout')

async function trace(source, target) {
  const estrace = await import('estrace/plugin');
  const newLine = await import('./setup/loaders/putout-new-line-plugin.js');
  const {code} = putout(await fs.promises.readFile(source, 'utf-8'), {
    fixCount: 1,
    rules: {
      estrace: ['on', { url: 'inline', exclude: [ 'FunctionExpression', 'ArrowFunctionExpression' ] }]
    },
    plugins: [
      [ 'estrace', estrace ],
      [ 'new-line', newLine ],
    ],
  })
  await fs.promises.writeFile(target, code)
}

async function main() {
  await trace('source.js', 'traced.js')
}

main()

traced.js

export function set(extra) {
  try {
    __estrace.enter('set', 'inline:1', arguments);
    extra += `
  ${prefix}${casing[field] || field}
  ${value.raw ? "=" : ":"} 
  ${value.value}`;
    return extra;
  } finally {
    __estrace.exit('set', 'inline:1');
  }
}