addSinon.js

function findImports (j, ast, pkg) {
    return ast.find(j.ImportDeclaration, {
        source: {
            value: pkg
        }
    })
}
/**
 * Detects CommonJS and import statements for the given package.
 * @return true if import were found, else false
 */
function hasRequireOrImport (j, ast, pkg) {
    // const requires = findRequires(j, ast, pkg).size()
    const imports = findImports(j, ast, pkg).size()
    return imports > 0
}

function hasIdentifier (j, ast, name) {
    return ast.find(j.Identifier, {
        name
    }).size() > 0
}

module.exports = function (fileInfo, api) {
    const j = api.jscodeshift
    const ast = j(fileInfo.source)

    if (!hasRequireOrImport(j, ast, 'sinon') && hasIdentifier(j, ast, 'sinon')) {
        let imp = ast.find(j.ImportDeclaration, {})
        // console.log(imp)

        let node = imp.at(imp.size() - 1)

        const {statement} = j.template
        // const newNode = j.importDeclaration('sinon', 'sinon');
        node.insertAfter(statement`import sinon from 'sinon'`)

        return node.toSource()
    }
}