ast-utils.ts

import { JSCodeshift, Node, valueType } from "./types/NodePath";
import * as validateIdentifier from "./validate-identifier";

/**
 *
 * Traverse safely over a path object for array for paths
 * @param {Object} obj - Object on which we traverse
 * @param {Array} paths - Array of strings containing the traversal path
 * @returns {Node} Value at given traversal path
 */

function safeTraverse(obj: Node, paths: string[]): Node | Node[] {
	// TODO: to revisit the type of this function, it's not clear what should return.
	// Sometimes its return type is used as string
	let val: Node = obj;
	let idx = 0;

	while (idx < paths.length) {
		if (!val) {
			return null;
		}
		val = val[paths[idx]];
		idx++;
	}
	return val;
}

/**
 *
 * Traverse safely and return `type` for path object with value.value property
 * @param {Node} path - AST node
 * @returns {String|Boolean} type at given path.
 */

function safeTraverseAndGetType(path: Node): string | boolean {
	const pathValue = safeTraverse(path, ["value", "value"]) as Node;
	return pathValue ? pathValue.type : false;
}

/**
 * Convert nested MemberExpressions to strings like webpack.optimize.DedupePlugin
 * @param {Node} path - AST node
 * @returns {String} member expression string.
 */

function memberExpressionToPathString(path: Node): string {
	if (path && path.object) {
		return [memberExpressionToPathString(path.object), path.property.name].join(".");
	}
	return path.name;
}

// Convert Array<string> like ['webpack', 'optimize', 'DedupePlugin'] to nested MemberExpressions
function pathsToMemberExpression(j: JSCodeshift, paths: string[]): Node {
	if (!paths.length) {
		return null;
	} else if (paths.length === 1) {
		return j.identifier(paths[0]);
	} else {
		const first: string[] = paths.slice(0, 1);
		const rest: string[] = paths.slice(1);
		return j.memberExpression(pathsToMemberExpression(j, rest), pathsToMemberExpression(j, first));
	}
}

/**
 *
 * Find paths that match `new name.space.PluginName()` for a
 * given array of plugin names
 *
 * @param {any} j — jscodeshift API
 * @param {Node} node - Node to start search from
 * @param {String[]} pluginNamesArray - Array of plugin names like `webpack.LoaderOptionsPlugin`
 * @returns {Node} Node that has the pluginName
 */

function findPluginsByName(j: JSCodeshift, node: Node, pluginNamesArray: string[]): Node {
	return node.find(j.NewExpression).filter(
		(path: Node): boolean => {
			return pluginNamesArray.some(
				(plugin: string): boolean => memberExpressionToPathString(path.get("callee").value as Node) === plugin
			);
		}
	);
}

/**
 * It lookouts for the plugins property and, if the array is empty, it removes it from the AST
 * @param  {any} j - jscodeshift API
 * @param  {Node} rootNode - node to start search from
 * @returns {Node} rootNode modified AST.
 */

function findPluginsArrayAndRemoveIfEmpty(j: JSCodeshift, rootNode: Node): Node {
	return rootNode.find(j.Identifier, { name: "plugins" }).forEach(
		(node: Node): void => {
			const elements = safeTraverse(node, ["parent", "value", "value", "elements"]) as Node[];
			if (!elements.length) {
				j(node.parent).remove();
			}
		}
	);
}

/**
 *
 * Finds the path to the `name: []` node
 *
 * @param {any} j — jscodeshift API
 * @param {Node} node - Node to start search from
 * @param {String} propName - property to search for
 * @returns {Node} found node and
 */

function findRootNodesByName(j: JSCodeshift, node: Node, propName: string): Node {
	return node.find(j.Property, { key: { name: propName } });
}

/**
 *
 * Creates an appropriate identifier or literal property
 *
 * @param {any} j — jscodeshift API
 * @param {String | Boolean | Number} val
 * @returns {Node}
 */

function createIdentifierOrLiteral(j: JSCodeshift, val: valueType): Node {
	// IPath<IIdentifier> | IPath<ILiteral> doesn't work, find another way
	let literalVal = val;
	// We'll need String to native type conversions
	if (!Array.isArray(val)) {
		if (typeof val === "string" || (typeof val === "object" && val.__paths)) {
			// 'true' => true
			if (val === "true") {
				literalVal = true;
				return j.literal(literalVal);
			}
			// 'false' => false
			if (val === "false") {
				literalVal = false;
				return j.literal(literalVal);
			}
			// '1' => 1
			if (!isNaN(Number(val))) {
				literalVal = Number(val);
				return j.literal(literalVal);
			}
			if (typeof val === "object" && val.__paths) {
				const regExpVal = ((val.__paths[0].value as JSCodeshift).program as Node).body[0].expression;
				return j.literal(regExpVal.value);
			} else if (typeof literalVal === "string") {
				// Use identifier instead
				if (
					!validateIdentifier.isKeyword(literalVal) ||
					!validateIdentifier.isIdentifierStart(literalVal) ||
					!validateIdentifier.isIdentifierChar(literalVal)
				) {
					return j.identifier(literalVal);
				}
			}
		}
	}
	return j.literal(literalVal);
}

/**
 *
 * Creates an appropriate literal property
 *
 * @param {any} j — jscodeshift API
 * @param {String | Boolean | Number} val
 * @returns {Node}
 */

function createLiteral(j: JSCodeshift, val: valueType): Node {
	let literalVal: valueType = val;
	// We'll need String to native type conversions
	if (typeof val === "string") {
		// 'true' => true
		if (val === "true") {
			literalVal = true;
		}
		// 'false' => false
		if (val === "false") {
			literalVal = false;
		}
		// '1' => 1
		if (!isNaN(Number(val))) {
			literalVal = Number(val);
		}
	}
	return j.literal(literalVal);
}

/**
 *
 * Creates an Object's property with a given key and value
 *
 * @param {any} j — jscodeshift API
 * @param {String | Number} key - Property key
 * @param {String | Number | Boolean} value - Property value
 * @returns {Node}
 */

function createProperty(j: JSCodeshift, key: string | number, value: valueType): Node {
	return j.property("init", createIdentifierOrLiteral(j, key), createLiteral(j, value));
}

/**
 *
 * Adds or updates the value of a key within a root
 * webpack configuration property that's of type Object.
 *
 * @param {any} j — jscodeshift API
 * @param {Node} rootNode - node of root webpack configuration
 * @param {String} configProperty - key of an Object webpack configuration property
 * @param {String} key - key within the configuration object to update
 * @param {Object} value - the value to set for the key
 * @returns {Void}
 */

function addOrUpdateConfigObject(
	j: JSCodeshift,
	rootNode: Node,
	configProperty: string,
	key: string,
	value: valueType
): void {
	const propertyExists = rootNode.properties.filter((node: Node): boolean => node.key.name === configProperty).length;

	if (propertyExists) {
		rootNode.properties
			.filter((path: Node): boolean => path.key.name === configProperty)
			.forEach(
				(path: Node): void => {
					const newProperties = (path.value as Node).properties.filter(
						(p: Node): boolean => p.key.name !== key
					);
					newProperties.push(j.objectProperty(j.identifier(key), value));
					(path.value as Node).properties = newProperties;
				}
			);
	} else {
		rootNode.properties.push(
			j.objectProperty(
				j.identifier(configProperty),
				j.objectExpression([j.objectProperty(j.identifier(key), value)])
			)
		);
	}
}

/**
 *
 * Finds and removes a node for a given plugin name. If the plugin
 * is the last in the plugins array, the array is also removed.
 *
 * @param {any} j — jscodeshift API
 * @param {Node} node - node to start search from
 * @param {String} pluginName - name of the plugin to remove
 * @returns {Node | Void} - path to the root webpack configuration object if plugin is found
 */

function findAndRemovePluginByName(j: JSCodeshift, node: Node, pluginName: string): Node {
	let rootPath: Node;

	findPluginsByName(j, node, [pluginName])
		.filter((path: Node): boolean => !!safeTraverse(path, ["parent", "value"]))
		.forEach(
			(path: Node): void => {
				rootPath = safeTraverse(path, ["parent", "parent", "parent", "value"]) as Node;
				const arrayPath = path.parent.value as Node;
				if (arrayPath.elements && arrayPath.elements.length === 1) {
					j(path.parent.parent).remove();
				} else {
					j(path).remove();
				}
			}
		);

	return rootPath;
}

/**
 *
 * Finds or creates a node for a given plugin name string with options object
 * If plugin declaration already exist, options are merged.
 *
 * @param {any} j — jscodeshift API
 * @param {Node} rootNodePath - `plugins: []` NodePath where plugin should be added.
 * 								See https://github.com/facebook/jscodeshift/wiki/jscodeshift-Documentation#nodepaths
 * @param {String} pluginName - ex. `webpack.LoaderOptionsPlugin`
 * @param {Object} options - plugin options
 * @returns {Void}
 */

function createOrUpdatePluginByName(j: JSCodeshift, rootNodePath: Node, pluginName: string, options?: object): void {
	const pluginInstancePath: Node = findPluginsByName(j, j(rootNodePath), [pluginName]);
	let optionsProps: Node[];
	if (options) {
		optionsProps = Object.keys(options).map(
			(key: string): Node => {
				return createProperty(j, key, options[key]);
			}
		);
	}

	// If plugin declaration already exist
	if (pluginInstancePath.size()) {
		pluginInstancePath.forEach(
			(path: Node): void => {
				// There are options we want to pass as argument
				if (optionsProps) {
					const args: Node[] = (path.value as Node).arguments;
					if (args.length) {
						// Plugin is called with object as arguments
						// we will merge those objects
						const currentProps: Node = j(path)
							.find(j.ObjectExpression)
							.get("properties");

						optionsProps.forEach(
							(opt: Node): void => {
								// Search for same keys in the existing object
								const existingProps = j(currentProps)
									.find(j.Identifier)
									.filter((p: Node): boolean => opt.key.value === (p.value as Node).name);

								if (existingProps.size()) {
									// Replacing values for the same key
									existingProps.forEach(
										(p: Node): void => {
											j(p.parent).replaceWith(opt);
										}
									);
								} else {
									// Adding new key:values
									(currentProps.value as Node[]).push(opt);
								}
							}
						);
					} else {
						// Plugin is called without arguments
						args.push(j.objectExpression(optionsProps));
					}
				}
			}
		);
	} else {
		let argumentsArray: Node[] = [];
		if (optionsProps) {
			argumentsArray = [j.objectExpression(optionsProps)];
		}
		const loaderPluginInstance = j.newExpression(
			pathsToMemberExpression(j, pluginName.split(".").reverse()),
			argumentsArray
		);
		(rootNodePath.value as Node).elements.push(loaderPluginInstance);
	}
}

/**
 *
 * Finds the variable to which a third party plugin is assigned to
 *
 * @param {any} j — jscodeshift API
 * @param {Node} rootNode - `plugins: []` Root Node.
 * 							See https://github.com/facebook/jscodeshift/wiki/jscodeshift-Documentation#nodepaths
 * @param {String} pluginPackageName - ex. `extract-text-plugin`
 * @returns {String} variable name - ex. 'const s = require(s) gives "s"`
 */

function findVariableToPlugin(j: JSCodeshift, rootNode: Node, pluginPackageName: string): string {
	const moduleVarNames: Node[] = rootNode
		.find(j.VariableDeclarator)
		.filter(j.filters.VariableDeclarator.requiresModule(pluginPackageName))
		.nodes();
	if (moduleVarNames.length === 0) {
		return null;
	}
	return moduleVarNames.pop().id.name;
}

/**
 *
 * Returns true if type is given type
 * @param {Node} path - AST node
 * @param {String} type - node type
 * @returns {Boolean}
 */

function isType(path: Node, type: string): boolean {
	return path.type === type;
}

function findObjWithOneOfKeys(p: Node, keyNames: string[]): boolean {
	return (p.value as Node).properties.reduce((predicate: boolean, prop: Node): boolean => {
		const name: string = prop.key.name;
		return keyNames.indexOf(name) > -1 || predicate;
	}, false);
}

/**
 *
 * Returns constructed require symbol
 * @param {any} j — jscodeshift API
 * @param {String} constName - Name of require
 * @param {String} packagePath - path of required package
 * @returns {Node} - the created ast
 */

function getRequire(j: JSCodeshift, constName: string, packagePath: string): Node {
	return j.variableDeclaration("const", [
		j.variableDeclarator(
			j.identifier(constName),
			j.callExpression(j.identifier("require"), [j.literal(packagePath)])
		)
	]);
}

/**
 *
 * Recursively adds an object/property to a node
 * @param {any} j — jscodeshift API
 * @param {Node} p - AST node
 * @param {String} key - key of a key/val object
 * @param {Any} value - Any type of object
 * @param {String} action - Action to be done on the given ast
 * @returns {Node} - the created ast
 */

function addProperty(j: JSCodeshift, p: Node, key: string, value: valueType, action?: string): Node {
	if (!p) {
		return;
	}
	let valForNode: valueType;
	if (Array.isArray(value)) {
		let arrExp: Node = j.arrayExpression([]);
		if (safeTraverseAndGetType(p) === "ArrayExpression") {
			arrExp = (p.value as Node).value as Node;
		}
		value.forEach(
			(val: valueType): void => {
				addProperty(j, arrExp, null, val);
			}
		);
		valForNode = arrExp;
	} else if (typeof value === "object" && !(value.__paths || value instanceof RegExp)) {
		let objectExp: Node = j.objectExpression([]);
		if (safeTraverseAndGetType(p) === "ObjectExpression") {
			objectExp = (p.value as Node).value as Node;
		}
		// object -> loop through it
		Object.keys(value).forEach(
			(prop: string): void => {
				addProperty(j, objectExp, prop, value[prop]);
			}
		);
		valForNode = objectExp;
	} else {
		valForNode = createIdentifierOrLiteral(j, value);
	}
	let pushVal: valueType;
	if (key) {
		pushVal = j.property("init", j.identifier(key), valForNode);
	} else {
		pushVal = valForNode;
	}

	// we only return the generated pushVal which will be replace the node path
	if (action === "add") {
		return pushVal;
	}

	if (p.properties) {
		p.properties.push(pushVal);
		return p;
	}
	if (p.value && (p.value as Node).properties) {
		(p.value as Node).properties.push(pushVal);
		return p;
	}
	if (p.elements) {
		p.elements.push(pushVal);
		return p;
	}
	return;
}

/**
 *
 * Removes an object/property from the config
 * @param {any} j — jscodeshift API
 * @param {Node} ast - AST node
 * @param {String} key - key of a key/val object
 * @param {Any} value - Any type of object
 * @returns {Node} - the created ast
 */

function removeProperty(j: JSCodeshift, ast: Node, key: string, value: valueType): Node {
	if (typeof value === "object" && !Array.isArray(value)) {
		// override for module.rules / loaders
		if (key === "module" && value.rules) {
			return ast
				.find(j.Property, {
					value: {
						type: "Literal",
						value: value.rules[0].loader
					}
				})
				.forEach(
					(p: Node): void => {
						j(p.parent).remove();
					}
				);
		}
	}

	// value => array
	if (Array.isArray(value)) {
		return ast
			.find(j.Literal, {
				value: value[0]
			})
			.forEach(
				(p: Node): void => {
					const configKey = safeTraverse(p, ["parent", "parent", "node", "key", "name"]);
					if (configKey === key) {
						j(p).remove();
					}
				}
			);
	}

	// value => literal string / boolean / nested object
	let objKeyToRemove: string | null = null;
	if (value === null) {
		objKeyToRemove = key;
	} else if (typeof value === "object") {
		for (const innerKey in value) {
			if (value[innerKey] === null) {
				objKeyToRemove = innerKey;
			}
		}
	}
	return ast
		.find(j.Property, {
			key: {
				name: objKeyToRemove,
				type: "Identifier"
			}
		})
		.forEach(
			(p: Node): void => {
				j(p).remove();
			}
		);
}

/**
 *
 * Get an property named topScope from yeoman and inject it to the top scope of
 * the config, outside module.exports
 *
 * @param j — jscodeshift API
 * @param ast - jscodeshift API
 * @param {any} value - transformation object to scaffold
 * @param {String} action - action that indicates what to be done to the AST
 * @returns ast - jscodeshift API
 */

// eslint-disable-next-line @typescript-eslint/no-unused-vars
function parseTopScope(j: JSCodeshift, ast: Node, value: string[], action: string): boolean | Node {
	function createTopScopeProperty(p: Node): boolean {
		value.forEach(
			(n: string): void => {
				if (
					!(p.value as Node).body[0].declarations ||
					n.indexOf((p.value as Node).body[0].declarations[0].id.name) <= 0
				) {
					(p.value as Node).body.splice(-1, 0, n);
				}
			}
		);
		return false; // TODO: debug later
	}
	if (value) {
		return ast.find(j.Program).filter((p: Node): boolean => createTopScopeProperty(p));
	} else {
		return ast;
	}
}

/**
 *
 * Transform for merge. Finds the merge property from yeoman and creates a way
 * for users to allow webpack-merge in their scaffold
 *
 * @param j — jscodeshift API
 * @param ast - jscodeshift API
 * @param {any} value - transformation object to scaffold
 * @param {String} action - action that indicates what to be done to the AST
 * @returns ast - jscodeshift API
 */

// eslint-disable-next-line @typescript-eslint/no-unused-vars
function parseMerge(j: JSCodeshift, ast: Node, value: string, action: string): boolean | Node {
	function createMergeProperty(p: Node): boolean {
		// FIXME Use j.callExp()
		const exportsDecl: Node[] = (p.value as Node).body.map(
			(n: Node): Node => {
				if (n.expression) {
					return n.expression.right;
				}
			}
		);
		const bodyLength = exportsDecl.length;
		const newVal: Node = {};
		newVal.type = "ExpressionStatement";
		newVal.expression = {
			left: {
				computed: false,
				object: j.identifier("module"),
				property: j.identifier("exports"),
				type: "MemberExpression"
			},
			operator: "=",
			right: j.callExpression(j.identifier("merge"), [j.identifier(value), exportsDecl.pop()]),
			type: "AssignmentExpression"
		};
		(p.value as Node).body[bodyLength - 1] = newVal;
		return false; // TODO: debug later
	}
	if (value) {
		return ast.find(j.Program).filter((p: Node): boolean => createMergeProperty(p));
	} else {
		return ast;
	}
}

export {
	safeTraverse,
	safeTraverseAndGetType,
	createProperty,
	findPluginsByName,
	findRootNodesByName,
	addOrUpdateConfigObject,
	findAndRemovePluginByName,
	createOrUpdatePluginByName,
	findVariableToPlugin,
	findPluginsArrayAndRemoveIfEmpty,
	isType,
	createLiteral,
	createIdentifierOrLiteral,
	findObjWithOneOfKeys,
	getRequire,
	addProperty,
	removeProperty,
	parseTopScope,
	parseMerge
};