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Expose /pure build that doesnt depend on OS or require
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@Andarist
Andarist committed Aug 26, 2022
1 parent e3bdfe0 commit a0e965b
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Showing 12 changed files with 431 additions and 421 deletions.
18 changes: 4 additions & 14 deletions lib/options.ts
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Original file line number Diff line number Diff line change
@@ -1,10 +1,8 @@
import { Omit } from "ast-types/types";

/**
* All Recast API functions take second parameter with configuration options,
* documented in options.js
*/
export interface Options extends DeprecatedOptions {
export interface Options {
/**
* If you want to use a different branch of esprima, or any other module
* that supports a .parse function, pass that module object to
Expand Down Expand Up @@ -159,17 +157,11 @@ export interface Options extends DeprecatedOptions {
tokens?: boolean;
}

interface DeprecatedOptions {
/** @deprecated */
esprima?: any;
}

const defaults: Options = {
parser: require("../parsers/esprima"),
tabWidth: 4,
useTabs: false,
reuseWhitespace: true,
lineTerminator: require("os").EOL || "\n",
lineTerminator: "\n",
wrapColumn: 74, // Aspirational for now.
sourceFileName: null,
sourceMapName: null,
Expand All @@ -187,9 +179,7 @@ const defaults: Options = {
};
const hasOwn = defaults.hasOwnProperty;

export type NormalizedOptions = Required<
Omit<Options, keyof DeprecatedOptions>
>;
export type NormalizedOptions = Required<Options>;

// Copy options and fill in default values.
export function normalize(opts?: Options): NormalizedOptions {
Expand All @@ -209,7 +199,7 @@ export function normalize(opts?: Options): NormalizedOptions {
sourceMapName: get("sourceMapName"),
sourceRoot: get("sourceRoot"),
inputSourceMap: get("inputSourceMap"),
parser: get("esprima") || get("parser"),
parser: get("parser"),
range: get("range"),
tolerant: get("tolerant"),
quote: get("quote"),
Expand Down
313 changes: 23 additions & 290 deletions lib/parser.ts
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Original file line number Diff line number Diff line change
@@ -1,295 +1,28 @@
import assert from "assert";
import * as types from "ast-types";
const b = types.builders;
const isObject = types.builtInTypes.object;
const isArray = types.builtInTypes.array;
import { normalize as normalizeOptions } from "./options";
import { fromString } from "./lines";
import { attach as attachComments } from "./comments";
import * as util from "./util";
import { Options } from "./options";
import { parse as pureParse } from "./pure-parser";
import { normalize as normalizeOptions } from "./options";

export function parse(source: string, options?: Partial<Options>) {
options = normalizeOptions(options);

const lines = fromString(source, options);

const sourceWithoutTabs = lines.toString({
tabWidth: options.tabWidth,
reuseWhitespace: false,
useTabs: false,
});

let comments: any[] = [];
const ast = options.parser.parse(sourceWithoutTabs, {
jsx: true,
loc: true,
locations: true,
range: options.range,
comment: true,
onComment: comments,
tolerant: util.getOption(options, "tolerant", true),
ecmaVersion: 6,
sourceType: util.getOption(options, "sourceType", "module"),
options = normalizeOptions({
parser: require("../parsers/esprima"),
...options,
});

// Use ast.tokens if possible, and otherwise fall back to the Esprima
// tokenizer. All the preconfigured ../parsers/* expose ast.tokens
// automatically, but custom parsers might need additional configuration
// to avoid this fallback.
const tokens: any[] = Array.isArray(ast.tokens)
? ast.tokens
: require("esprima").tokenize(sourceWithoutTabs, {
loc: true,
});

// We will reattach the tokens array to the file object below.
delete ast.tokens;

// Make sure every token has a token.value string.
tokens.forEach(function (token) {
if (typeof token.value !== "string") {
token.value = lines.sliceString(token.loc.start, token.loc.end);
}
});

if (Array.isArray(ast.comments)) {
comments = ast.comments;
delete ast.comments;
}

if (ast.loc) {
// If the source was empty, some parsers give loc.{start,end}.line
// values of 0, instead of the minimum of 1.
util.fixFaultyLocations(ast, lines);
} else {
ast.loc = {
start: lines.firstPos(),
end: lines.lastPos(),
};
}

ast.loc.lines = lines;
ast.loc.indent = 0;

let file;
let program;
if (ast.type === "Program") {
program = ast;
// In order to ensure we reprint leading and trailing program
// comments, wrap the original Program node with a File node. Only
// ESTree parsers (Acorn and Esprima) return a Program as the root AST
// node. Most other (Babylon-like) parsers return a File.
file = b.file(ast, options.sourceFileName || null);
file.loc = {
start: lines.firstPos(),
end: lines.lastPos(),
lines: lines,
indent: 0,
} as any;
} else if (ast.type === "File") {
file = ast;
program = file.program;
}

// Expose file.tokens unless the caller passed false for options.tokens.
if (options.tokens) {
file.tokens = tokens;
}

// Expand the Program's .loc to include all comments (not just those
// attached to the Program node, as its children may have comments as
// well), since sometimes program.loc.{start,end} will coincide with the
// .loc.{start,end} of the first and last *statements*, mistakenly
// excluding comments that fall outside that region.
const trueProgramLoc: any = util.getTrueLoc(
{
type: program.type,
loc: program.loc,
body: [],
comments,
},
lines,
);
program.loc.start = trueProgramLoc.start;
program.loc.end = trueProgramLoc.end;

// Passing file.program here instead of just file means that initial
// comments will be attached to program.body[0] instead of program.
attachComments(comments, program.body.length ? file.program : file, lines);

// Return a copy of the original AST so that any changes made may be
// compared to the original.
return new TreeCopier(lines, tokens).copy(file);
let original = options.parser.parse.bind(options.parser);
options.parser.parse = (source: string, options: any) => {
const ast = original(source, options);
// Use ast.tokens if possible, and otherwise fall back to the Esprima
// tokenizer. All the preconfigured ../parsers/* expose ast.tokens
// automatically, but custom parsers might need additional configuration
// to avoid this fallback.
const tokens: any[] = Array.isArray(ast.tokens)
? ast.tokens
: require("esprima").tokenize(source, {
loc: true,
});

ast.tokens = tokens;

return ast;
};
return pureParse(source, options);
}

interface TreeCopierType {
lines: any;
tokens: any[];
startTokenIndex: number;
endTokenIndex: number;
indent: number;
seen: Map<any, any>;
copy(node: any): any;
findTokenRange(loc: any): any;
}

interface TreeCopierConstructor {
new (lines: any, tokens: any): TreeCopierType;
}

const TreeCopier = function TreeCopier(
this: TreeCopierType,
lines: any,
tokens: any,
) {
assert.ok(this instanceof TreeCopier);
this.lines = lines;
this.tokens = tokens;
this.startTokenIndex = 0;
this.endTokenIndex = tokens.length;
this.indent = 0;
this.seen = new Map();
} as any as TreeCopierConstructor;

const TCp: TreeCopierType = TreeCopier.prototype;

TCp.copy = function (node) {
if (this.seen.has(node)) {
return this.seen.get(node);
}

if (isArray.check(node)) {
const copy: any = new Array(node.length);
this.seen.set(node, copy);
node.forEach(function (this: any, item: any, i: any) {
copy[i] = this.copy(item);
}, this);
return copy;
}

if (!isObject.check(node)) {
return node;
}

util.fixFaultyLocations(node, this.lines);

const copy: any = Object.create(Object.getPrototypeOf(node), {
original: {
// Provide a link from the copy to the original.
value: node,
configurable: false,
enumerable: false,
writable: true,
},
});

this.seen.set(node, copy);

const loc = node.loc;
const oldIndent = this.indent;
let newIndent = oldIndent;

const oldStartTokenIndex = this.startTokenIndex;
const oldEndTokenIndex = this.endTokenIndex;

if (loc) {
// When node is a comment, we set node.loc.indent to
// node.loc.start.column so that, when/if we print the comment by
// itself, we can strip that much whitespace from the left margin of
// the comment. This only really matters for multiline Block comments,
// but it doesn't hurt for Line comments.
if (
node.type === "Block" ||
node.type === "Line" ||
node.type === "CommentBlock" ||
node.type === "CommentLine" ||
this.lines.isPrecededOnlyByWhitespace(loc.start)
) {
newIndent = this.indent = loc.start.column;
}

// Every node.loc has a reference to the original source lines as well
// as a complete list of source tokens.
loc.lines = this.lines;
loc.tokens = this.tokens;
loc.indent = newIndent;

// Set loc.start.token and loc.end.token such that
// loc.tokens.slice(loc.start.token, loc.end.token) returns a list of
// all the tokens that make up this node.
this.findTokenRange(loc);
}

const keys = Object.keys(node);
const keyCount = keys.length;
for (let i = 0; i < keyCount; ++i) {
const key = keys[i];
if (key === "loc") {
copy[key] = node[key];
} else if (key === "tokens" && node.type === "File") {
// Preserve file.tokens (uncopied) in case client code cares about
// it, even though Recast ignores it when reprinting.
copy[key] = node[key];
} else {
copy[key] = this.copy(node[key]);
}
}

this.indent = oldIndent;
this.startTokenIndex = oldStartTokenIndex;
this.endTokenIndex = oldEndTokenIndex;

return copy;
};

// If we didn't have any idea where in loc.tokens to look for tokens
// contained by this loc, a binary search would be appropriate, but
// because we maintain this.startTokenIndex and this.endTokenIndex as we
// traverse the AST, we only need to make small (linear) adjustments to
// those indexes with each recursive iteration.
TCp.findTokenRange = function (loc) {
// In the unlikely event that loc.tokens[this.startTokenIndex] starts
// *after* loc.start, we need to rewind this.startTokenIndex first.
while (this.startTokenIndex > 0) {
const token = loc.tokens[this.startTokenIndex];
if (util.comparePos(loc.start, token.loc.start) < 0) {
--this.startTokenIndex;
} else break;
}

// In the unlikely event that loc.tokens[this.endTokenIndex - 1] ends
// *before* loc.end, we need to fast-forward this.endTokenIndex first.
while (this.endTokenIndex < loc.tokens.length) {
const token = loc.tokens[this.endTokenIndex];
if (util.comparePos(token.loc.end, loc.end) < 0) {
++this.endTokenIndex;
} else break;
}

// Increment this.startTokenIndex until we've found the first token
// contained by this node.
while (this.startTokenIndex < this.endTokenIndex) {
const token = loc.tokens[this.startTokenIndex];
if (util.comparePos(token.loc.start, loc.start) < 0) {
++this.startTokenIndex;
} else break;
}

// Index into loc.tokens of the first token within this node.
loc.start.token = this.startTokenIndex;

// Decrement this.endTokenIndex until we've found the first token after
// this node (not contained by the node).
while (this.endTokenIndex > this.startTokenIndex) {
const token = loc.tokens[this.endTokenIndex - 1];
if (util.comparePos(loc.end, token.loc.end) < 0) {
--this.endTokenIndex;
} else break;
}

// Index into loc.tokens of the first token *after* this node.
// If loc.start.token === loc.end.token, the node contains no tokens,
// and the index is that of the next token following this node.
loc.end.token = this.endTokenIndex;
};
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