Eslint function-multiline-arguments

function-multiline-arguments.js

module.exports = {
  rules: {
    'function-multiline-arguments': {
      meta: {
        type: 'layout',
        fixable: 'code',
        schema: [] // no options
      },
      create: context => ({
        CallExpression: node => {
          if (node.arguments.length <= 1) return;
          let startLine = node.callee.loc.end.line;
          let endLine = node.loc.end.line;
          if (startLine == endLine) return;
          let argLines = node.arguments
            .flatMap(
              node => node.loc.start.line == node.loc.end.line
                ? [node.loc.start.line]
                : [node.loc.start.line, node.loc.end.line]
            );
          let endsInFunction = !!node.arguments[node.arguments.length -1].body;
          if (new Set(argLines.slice(0, -1)).size == 1 && endsInFunction) return;
          argLines.push(startLine);
          argLines.push(endLine);
          if (new Set(argLines).size == argLines.length) return;
          context.report({
            node,
            message: 'Function arguments covering multiple lines should each start on a new line',
            fix(fixer) {
              let actions = [];
              node.arguments.forEach(
                (arg, i, arr) => {
                  let prev = i == 0? startLine : arr[i-1].loc.end.line;
                  if (arg.loc.start.line == prev) {
                    actions.push(fixer.insertTextBefore(arg, '\n'));
                  }
                }
              );
              let lastArg = node.arguments[node.arguments.length -1];
              if (lastArg.loc.start.line == endLine) {
                actions.push(fixer.insertTextAfter(lastArg, '\n'));
              }
              return actions;
            }
          });
        }
      })
    }
  }
};