plugin.js

import {realpathSync} from 'fs';
import {programVisitor} from 'istanbul-lib-instrument';

function getRealpath(n) {
    try {
        return realpathSync(n) || n
    } catch (e) {
        return n
    }
}

function shouldSkip(file) {
    return false;
}

function makeVisitor({types: t}) {
    return {
        visitor: {
            Program: {
                enter(path) {
                    this.__dv__ = null;
                    const realPath = getRealpath(this.file.opts.filename);
                    if (shouldSkip(realPath)) {
                        return;
                    }
                    this.__dv__ = programVisitor(t, realPath);
                    this.__dv__.enter(path);
                },
                exit(path) {
                    if (!this.__dv__) {
                        return;
                    }
                    this.__dv__.exit(path);
                }
            }
        }
    };
}

export default makeVisitor;