index.js

/**
 * babel-plugin-empower-assert
 *   Babel plugin to convert assert to power-assert at compile time
 * 
 * https://github.com/power-assert-js/babel-plugin-empower-assert
 *
 * Copyright (c) 2016-2018 Takuto Wada
 * Licensed under the MIT license.
 *   https://github.com/power-assert-js/babel-plugin-empower-assert/blob/master/LICENSE
 */
'use strict';

var declare = require('@babel/helper-plugin-utils').declare;

module.exports = declare(function (api, options, dirname) {
    api.assertVersion(7);
    return {
        visitor: {
            AssignmentExpression: {
                enter: function (nodePath, pluginPass) {
                    if (!nodePath.equals('operator', '=')) {
                        return;
                    }
                    var left = nodePath.get('left');
                    if (!left.isIdentifier()) {
                        return;
                    }
                    if (!left.equals('name', 'assert')) {
                        return;
                    }
                    replaceAssertIfMatch(nodePath.get('right'));
                }
            },
            VariableDeclarator: {
                enter: function (nodePath, pluginPass) {
                    var id = nodePath.get('id');
                    if (!id.isIdentifier()) {
                        return;
                    }
                    if (!id.equals('name', 'assert')) {
                        return;
                    }
                    replaceAssertIfMatch(nodePath.get('init'));
                }
            },
            ImportDeclaration: {
                enter: function (nodePath, pluginPass) {
                    var source = nodePath.get('source');
                    if (!(source.equals('value', 'assert'))) {
                        return;
                    }
                    source.set('value', 'power-assert');
                }
            }
        }
    };
});

function replaceAssertIfMatch (node) {
    var target;
    if (node.isCallExpression()) {
        target = node;
    } else if (node.isMemberExpression()) {
        target = node.get('object');
    } else {
        return;
    }
    var callee = target.get('callee');
    var arg = target.get('arguments')[0];
    if (isRequireAssert(callee, arg)) {
        arg.set('value', 'power-assert');
    }
}

function isRequireAssert (callee, arg) {
    if (!callee.isIdentifier() || !callee.equals('name', 'require')) {
        return false;
    }
    return (arg.isLiteral() && arg.equals('value', 'assert'));
}