forked from babel/babel
/
modification.ts
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/
modification.ts
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// This file contains methods that modify the path/node in some ways.
import { path as pathCache } from "../cache";
import PathHoister from "./lib/hoister";
import NodePath from "./index";
import * as t from "@babel/types";
import type Scope from "../scope";
/**
* Insert the provided nodes before the current one.
*/
export function insertBefore(this: NodePath, nodes_: t.Node | t.Node[]) {
this._assertUnremoved();
const nodes = this._verifyNodeList(nodes_);
const { parentPath } = this;
if (
parentPath.isExpressionStatement() ||
parentPath.isLabeledStatement() ||
parentPath.isExportNamedDeclaration() ||
(parentPath.isExportDefaultDeclaration() && this.isDeclaration())
) {
return parentPath.insertBefore(nodes);
} else if (
(this.isNodeType("Expression") && !this.isJSXElement()) ||
(parentPath.isForStatement() && this.key === "init")
) {
if (this.node) nodes.push(this.node);
// @ts-expect-error todo(flow->ts): check that nodes is an array of statements
return this.replaceExpressionWithStatements(nodes);
} else if (Array.isArray(this.container)) {
return this._containerInsertBefore(nodes);
} else if (this.isStatementOrBlock()) {
const node = this.node as t.Statement;
const shouldInsertCurrentNode =
node &&
(!this.isExpressionStatement() ||
(node as t.ExpressionStatement).expression != null);
this.replaceWith(t.blockStatement(shouldInsertCurrentNode ? [node] : []));
return this.unshiftContainer("body", nodes);
} else {
throw new Error(
"We don't know what to do with this node type. " +
"We were previously a Statement but we can't fit in here?",
);
}
}
export function _containerInsert(this: NodePath, from, nodes) {
this.updateSiblingKeys(from, nodes.length);
const paths = [];
// @ts-expect-error todo(flow->ts): this.container could be a NodePath
this.container.splice(from, 0, ...nodes);
for (let i = 0; i < nodes.length; i++) {
const to = from + i;
const path = this.getSibling(to);
paths.push(path);
if (this.context && this.context.queue) {
path.pushContext(this.context);
}
}
const contexts = this._getQueueContexts();
for (const path of paths) {
path.setScope();
path.debug("Inserted.");
for (const context of contexts) {
context.maybeQueue(path, true);
}
}
return paths;
}
export function _containerInsertBefore(this: NodePath, nodes) {
return this._containerInsert(this.key, nodes);
}
export function _containerInsertAfter(this: NodePath, nodes) {
// @ts-expect-error todo(flow->ts): this.key could be a string
return this._containerInsert(this.key + 1, nodes);
}
/**
* Insert the provided nodes after the current one. When inserting nodes after an
* expression, ensure that the completion record is correct by pushing the current node.
*/
export function insertAfter(
this: NodePath,
nodes_: t.Node | t.Node[],
): NodePath[] {
this._assertUnremoved();
const nodes = this._verifyNodeList(nodes_);
const { parentPath } = this;
if (
parentPath.isExpressionStatement() ||
parentPath.isLabeledStatement() ||
parentPath.isExportNamedDeclaration() ||
(parentPath.isExportDefaultDeclaration() && this.isDeclaration())
) {
return parentPath.insertAfter(
nodes.map(node => {
// Usually after an expression we can safely insert another expression:
// A.insertAfter(B)
// foo = A; -> foo = (A, B);
// If A is an expression statement, it isn't safe anymore so we need to
// convert B to an expression statement
// A; -> A; B // No semicolon! It could break if followed by [!
return t.isExpression(node) ? t.expressionStatement(node) : node;
}),
);
} else if (
(this.isNodeType("Expression") &&
!this.isJSXElement() &&
!parentPath.isJSXElement()) ||
(parentPath.isForStatement() && this.key === "init")
) {
if (this.node) {
const node = this.node as t.Expression | t.VariableDeclaration;
let { scope } = this;
if (scope.path.isPattern()) {
t.assertExpression(node);
this.replaceWith(
t.callExpression(t.arrowFunctionExpression([], node), []),
);
(this.get("callee.body") as NodePath).insertAfter(nodes);
return [this];
}
// Inserting after the computed key of a method should insert the
// temporary binding in the method's parent's scope.
if (parentPath.isMethod({ computed: true, key: node })) {
scope = scope.parent;
}
const temp = scope.generateDeclaredUidIdentifier();
nodes.unshift(
t.expressionStatement(
// @ts-expect-error todo(flow->ts): This can be a variable
// declaraion in the "init" of a for statement, but that's
// invalid here.
t.assignmentExpression("=", t.cloneNode(temp), node),
),
);
nodes.push(t.expressionStatement(t.cloneNode(temp)));
}
// @ts-expect-error todo(flow->ts): check that nodes is an array of statements
return this.replaceExpressionWithStatements(nodes);
} else if (Array.isArray(this.container)) {
return this._containerInsertAfter(nodes);
} else if (this.isStatementOrBlock()) {
const node = this.node as t.Statement;
const shouldInsertCurrentNode =
node &&
(!this.isExpressionStatement() ||
(node as t.ExpressionStatement).expression != null);
this.replaceWith(t.blockStatement(shouldInsertCurrentNode ? [node] : []));
return this.pushContainer("body", nodes);
} else {
throw new Error(
"We don't know what to do with this node type. " +
"We were previously a Statement but we can't fit in here?",
);
}
}
/**
* Update all sibling node paths after `fromIndex` by `incrementBy`.
*/
export function updateSiblingKeys(
this: NodePath,
fromIndex: number,
incrementBy: number,
) {
if (!this.parent) return;
const paths = pathCache.get(this.parent);
for (const [, path] of paths) {
if (path.key >= fromIndex) {
path.key += incrementBy;
}
}
}
export function _verifyNodeList(
this: NodePath,
nodes: t.Node | t.Node[],
): t.Node[] {
if (!nodes) {
return [];
}
if (!Array.isArray(nodes)) {
nodes = [nodes];
}
for (let i = 0; i < nodes.length; i++) {
const node = nodes[i];
let msg;
if (!node) {
msg = "has falsy node";
} else if (typeof node !== "object") {
msg = "contains a non-object node";
} else if (!node.type) {
msg = "without a type";
} else if (node instanceof NodePath) {
msg = "has a NodePath when it expected a raw object";
}
if (msg) {
const type = Array.isArray(node) ? "array" : typeof node;
throw new Error(
`Node list ${msg} with the index of ${i} and type of ${type}`,
);
}
}
return nodes;
}
export function unshiftContainer<Nodes extends t.Node | t.Node[]>(
listKey: string,
nodes: Nodes,
): NodePath[] {
// todo: NodePaths<Nodes>
this._assertUnremoved();
nodes = this._verifyNodeList(nodes);
// get the first path and insert our nodes before it, if it doesn't exist then it
// doesn't matter, our nodes will be inserted anyway
const path = NodePath.get({
parentPath: this,
parent: this.node,
container: this.node[listKey],
listKey,
key: 0,
}).setContext(this.context);
return path._containerInsertBefore(nodes);
}
export function pushContainer(
this: NodePath,
listKey: string,
nodes: t.Node | t.Node[],
) {
this._assertUnremoved();
const verifiedNodes = this._verifyNodeList(nodes);
// get an invisible path that represents the last node + 1 and replace it with our
// nodes, effectively inlining it
const container = this.node[listKey];
const path = NodePath.get({
parentPath: this,
parent: this.node,
container: container,
listKey,
key: container.length,
}).setContext(this.context);
return path.replaceWithMultiple(verifiedNodes);
}
/**
* Hoist the current node to the highest scope possible and return a UID
* referencing it.
*/
export function hoist<T extends t.Node>(
this: NodePath<T>,
scope: Scope = this.scope,
) {
const hoister = new PathHoister<T>(this, scope);
return hoister.run();
}