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- "use strict";
- Object.defineProperty(exports, "__esModule", { value: true });
- exports.getReprinter = exports.Patcher = void 0;
- var tslib_1 = require("tslib");
- var assert_1 = tslib_1.__importDefault(require("assert"));
- var linesModule = tslib_1.__importStar(require("./lines"));
- var types = tslib_1.__importStar(require("ast-types"));
- var Printable = types.namedTypes.Printable;
- var Expression = types.namedTypes.Expression;
- var ReturnStatement = types.namedTypes.ReturnStatement;
- var SourceLocation = types.namedTypes.SourceLocation;
- var util_1 = require("./util");
- var fast_path_1 = tslib_1.__importDefault(require("./fast-path"));
- var isObject = types.builtInTypes.object;
- var isArray = types.builtInTypes.array;
- var isString = types.builtInTypes.string;
- var riskyAdjoiningCharExp = /[0-9a-z_$]/i;
- var Patcher = function Patcher(lines) {
- assert_1.default.ok(this instanceof Patcher);
- assert_1.default.ok(lines instanceof linesModule.Lines);
- var self = this, replacements = [];
- self.replace = function (loc, lines) {
- if (isString.check(lines))
- lines = linesModule.fromString(lines);
- replacements.push({
- lines: lines,
- start: loc.start,
- end: loc.end,
- });
- };
- self.get = function (loc) {
- // If no location is provided, return the complete Lines object.
- loc = loc || {
- start: { line: 1, column: 0 },
- end: { line: lines.length, column: lines.getLineLength(lines.length) },
- };
- var sliceFrom = loc.start, toConcat = [];
- function pushSlice(from, to) {
- assert_1.default.ok((0, util_1.comparePos)(from, to) <= 0);
- toConcat.push(lines.slice(from, to));
- }
- replacements
- .sort(function (a, b) { return (0, util_1.comparePos)(a.start, b.start); })
- .forEach(function (rep) {
- if ((0, util_1.comparePos)(sliceFrom, rep.start) > 0) {
- // Ignore nested replacement ranges.
- }
- else {
- pushSlice(sliceFrom, rep.start);
- toConcat.push(rep.lines);
- sliceFrom = rep.end;
- }
- });
- pushSlice(sliceFrom, loc.end);
- return linesModule.concat(toConcat);
- };
- };
- exports.Patcher = Patcher;
- var Pp = Patcher.prototype;
- Pp.tryToReprintComments = function (newNode, oldNode, print) {
- var patcher = this;
- if (!newNode.comments && !oldNode.comments) {
- // We were (vacuously) able to reprint all the comments!
- return true;
- }
- var newPath = fast_path_1.default.from(newNode);
- var oldPath = fast_path_1.default.from(oldNode);
- newPath.stack.push("comments", getSurroundingComments(newNode));
- oldPath.stack.push("comments", getSurroundingComments(oldNode));
- var reprints = [];
- var ableToReprintComments = findArrayReprints(newPath, oldPath, reprints);
- // No need to pop anything from newPath.stack or oldPath.stack, since
- // newPath and oldPath are fresh local variables.
- if (ableToReprintComments && reprints.length > 0) {
- reprints.forEach(function (reprint) {
- var oldComment = reprint.oldPath.getValue();
- assert_1.default.ok(oldComment.leading || oldComment.trailing);
- patcher.replace(oldComment.loc,
- // Comments can't have .comments, so it doesn't matter whether we
- // print with comments or without.
- print(reprint.newPath).indentTail(oldComment.loc.indent));
- });
- }
- return ableToReprintComments;
- };
- // Get all comments that are either leading or trailing, ignoring any
- // comments that occur inside node.loc. Returns an empty array for nodes
- // with no leading or trailing comments.
- function getSurroundingComments(node) {
- var result = [];
- if (node.comments && node.comments.length > 0) {
- node.comments.forEach(function (comment) {
- if (comment.leading || comment.trailing) {
- result.push(comment);
- }
- });
- }
- return result;
- }
- Pp.deleteComments = function (node) {
- if (!node.comments) {
- return;
- }
- var patcher = this;
- node.comments.forEach(function (comment) {
- if (comment.leading) {
- // Delete leading comments along with any trailing whitespace they
- // might have.
- patcher.replace({
- start: comment.loc.start,
- end: node.loc.lines.skipSpaces(comment.loc.end, false, false),
- }, "");
- }
- else if (comment.trailing) {
- // Delete trailing comments along with any leading whitespace they
- // might have.
- patcher.replace({
- start: node.loc.lines.skipSpaces(comment.loc.start, true, false),
- end: comment.loc.end,
- }, "");
- }
- });
- };
- function getReprinter(path) {
- assert_1.default.ok(path instanceof fast_path_1.default);
- // Make sure that this path refers specifically to a Node, rather than
- // some non-Node subproperty of a Node.
- var node = path.getValue();
- if (!Printable.check(node))
- return;
- var orig = node.original;
- var origLoc = orig && orig.loc;
- var lines = origLoc && origLoc.lines;
- var reprints = [];
- if (!lines || !findReprints(path, reprints))
- return;
- return function (print) {
- var patcher = new Patcher(lines);
- reprints.forEach(function (reprint) {
- var newNode = reprint.newPath.getValue();
- var oldNode = reprint.oldPath.getValue();
- SourceLocation.assert(oldNode.loc, true);
- var needToPrintNewPathWithComments = !patcher.tryToReprintComments(newNode, oldNode, print);
- if (needToPrintNewPathWithComments) {
- // Since we were not able to preserve all leading/trailing
- // comments, we delete oldNode's comments, print newPath with
- // comments, and then patch the resulting lines where oldNode used
- // to be.
- patcher.deleteComments(oldNode);
- }
- var newLines = print(reprint.newPath, {
- includeComments: needToPrintNewPathWithComments,
- // If the oldNode we're replacing already had parentheses, we may
- // not need to print the new node with any extra parentheses,
- // because the existing parentheses will suffice. However, if the
- // newNode has a different type than the oldNode, let the printer
- // decide if reprint.newPath needs parentheses, as usual.
- avoidRootParens: oldNode.type === newNode.type && reprint.oldPath.hasParens(),
- }).indentTail(oldNode.loc.indent);
- var nls = needsLeadingSpace(lines, oldNode.loc, newLines);
- var nts = needsTrailingSpace(lines, oldNode.loc, newLines);
- // If we try to replace the argument of a ReturnStatement like
- // return"asdf" with e.g. a literal null expression, we run the risk
- // of ending up with returnnull, so we need to add an extra leading
- // space in situations where that might happen. Likewise for
- // "asdf"in obj. See #170.
- if (nls || nts) {
- var newParts = [];
- nls && newParts.push(" ");
- newParts.push(newLines);
- nts && newParts.push(" ");
- newLines = linesModule.concat(newParts);
- }
- patcher.replace(oldNode.loc, newLines);
- });
- // Recall that origLoc is the .loc of an ancestor node that is
- // guaranteed to contain all the reprinted nodes and comments.
- var patchedLines = patcher.get(origLoc).indentTail(-orig.loc.indent);
- if (path.needsParens()) {
- return linesModule.concat(["(", patchedLines, ")"]);
- }
- return patchedLines;
- };
- }
- exports.getReprinter = getReprinter;
- // If the last character before oldLoc and the first character of newLines
- // are both identifier characters, they must be separated by a space,
- // otherwise they will most likely get fused together into a single token.
- function needsLeadingSpace(oldLines, oldLoc, newLines) {
- var posBeforeOldLoc = (0, util_1.copyPos)(oldLoc.start);
- // The character just before the location occupied by oldNode.
- var charBeforeOldLoc = oldLines.prevPos(posBeforeOldLoc) && oldLines.charAt(posBeforeOldLoc);
- // First character of the reprinted node.
- var newFirstChar = newLines.charAt(newLines.firstPos());
- return (charBeforeOldLoc &&
- riskyAdjoiningCharExp.test(charBeforeOldLoc) &&
- newFirstChar &&
- riskyAdjoiningCharExp.test(newFirstChar));
- }
- // If the last character of newLines and the first character after oldLoc
- // are both identifier characters, they must be separated by a space,
- // otherwise they will most likely get fused together into a single token.
- function needsTrailingSpace(oldLines, oldLoc, newLines) {
- // The character just after the location occupied by oldNode.
- var charAfterOldLoc = oldLines.charAt(oldLoc.end);
- var newLastPos = newLines.lastPos();
- // Last character of the reprinted node.
- var newLastChar = newLines.prevPos(newLastPos) && newLines.charAt(newLastPos);
- return (newLastChar &&
- riskyAdjoiningCharExp.test(newLastChar) &&
- charAfterOldLoc &&
- riskyAdjoiningCharExp.test(charAfterOldLoc));
- }
- function findReprints(newPath, reprints) {
- var newNode = newPath.getValue();
- Printable.assert(newNode);
- var oldNode = newNode.original;
- Printable.assert(oldNode);
- assert_1.default.deepEqual(reprints, []);
- if (newNode.type !== oldNode.type) {
- return false;
- }
- var oldPath = new fast_path_1.default(oldNode);
- var canReprint = findChildReprints(newPath, oldPath, reprints);
- if (!canReprint) {
- // Make absolutely sure the calling code does not attempt to reprint
- // any nodes.
- reprints.length = 0;
- }
- return canReprint;
- }
- function findAnyReprints(newPath, oldPath, reprints) {
- var newNode = newPath.getValue();
- var oldNode = oldPath.getValue();
- if (newNode === oldNode)
- return true;
- if (isArray.check(newNode))
- return findArrayReprints(newPath, oldPath, reprints);
- if (isObject.check(newNode))
- return findObjectReprints(newPath, oldPath, reprints);
- return false;
- }
- function findArrayReprints(newPath, oldPath, reprints) {
- var newNode = newPath.getValue();
- var oldNode = oldPath.getValue();
- if (newNode === oldNode ||
- newPath.valueIsDuplicate() ||
- oldPath.valueIsDuplicate()) {
- return true;
- }
- isArray.assert(newNode);
- var len = newNode.length;
- if (!(isArray.check(oldNode) && oldNode.length === len))
- return false;
- for (var i = 0; i < len; ++i) {
- newPath.stack.push(i, newNode[i]);
- oldPath.stack.push(i, oldNode[i]);
- var canReprint = findAnyReprints(newPath, oldPath, reprints);
- newPath.stack.length -= 2;
- oldPath.stack.length -= 2;
- if (!canReprint) {
- return false;
- }
- }
- return true;
- }
- function findObjectReprints(newPath, oldPath, reprints) {
- var newNode = newPath.getValue();
- isObject.assert(newNode);
- if (newNode.original === null) {
- // If newNode.original node was set to null, reprint the node.
- return false;
- }
- var oldNode = oldPath.getValue();
- if (!isObject.check(oldNode))
- return false;
- if (newNode === oldNode ||
- newPath.valueIsDuplicate() ||
- oldPath.valueIsDuplicate()) {
- return true;
- }
- if (Printable.check(newNode)) {
- if (!Printable.check(oldNode)) {
- return false;
- }
- var newParentNode = newPath.getParentNode();
- var oldParentNode = oldPath.getParentNode();
- if (oldParentNode !== null &&
- oldParentNode.type === "FunctionTypeAnnotation" &&
- newParentNode !== null &&
- newParentNode.type === "FunctionTypeAnnotation") {
- var oldNeedsParens = oldParentNode.params.length !== 1 || !!oldParentNode.params[0].name;
- var newNeedParens = newParentNode.params.length !== 1 || !!newParentNode.params[0].name;
- if (!oldNeedsParens && newNeedParens) {
- return false;
- }
- }
- // Here we need to decide whether the reprinted code for newNode is
- // appropriate for patching into the location of oldNode.
- if (newNode.type === oldNode.type) {
- var childReprints = [];
- if (findChildReprints(newPath, oldPath, childReprints)) {
- reprints.push.apply(reprints, childReprints);
- }
- else if (oldNode.loc) {
- // If we have no .loc information for oldNode, then we won't be
- // able to reprint it.
- reprints.push({
- oldPath: oldPath.copy(),
- newPath: newPath.copy(),
- });
- }
- else {
- return false;
- }
- return true;
- }
- if (Expression.check(newNode) &&
- Expression.check(oldNode) &&
- // If we have no .loc information for oldNode, then we won't be
- // able to reprint it.
- oldNode.loc) {
- // If both nodes are subtypes of Expression, then we should be able
- // to fill the location occupied by the old node with code printed
- // for the new node with no ill consequences.
- reprints.push({
- oldPath: oldPath.copy(),
- newPath: newPath.copy(),
- });
- return true;
- }
- // The nodes have different types, and at least one of the types is
- // not a subtype of the Expression type, so we cannot safely assume
- // the nodes are syntactically interchangeable.
- return false;
- }
- return findChildReprints(newPath, oldPath, reprints);
- }
- function findChildReprints(newPath, oldPath, reprints) {
- var newNode = newPath.getValue();
- var oldNode = oldPath.getValue();
- isObject.assert(newNode);
- isObject.assert(oldNode);
- if (newNode.original === null) {
- // If newNode.original node was set to null, reprint the node.
- return false;
- }
- // If this node needs parentheses and will not be wrapped with
- // parentheses when reprinted, then return false to skip reprinting and
- // let it be printed generically.
- if (newPath.needsParens() && !oldPath.hasParens()) {
- return false;
- }
- var keys = (0, util_1.getUnionOfKeys)(oldNode, newNode);
- if (oldNode.type === "File" || newNode.type === "File") {
- // Don't bother traversing file.tokens, an often very large array
- // returned by Babylon, and useless for our purposes.
- delete keys.tokens;
- }
- // Don't bother traversing .loc objects looking for reprintable nodes.
- delete keys.loc;
- var originalReprintCount = reprints.length;
- for (var k in keys) {
- if (k.charAt(0) === "_") {
- // Ignore "private" AST properties added by e.g. Babel plugins and
- // parsers like Babylon.
- continue;
- }
- newPath.stack.push(k, types.getFieldValue(newNode, k));
- oldPath.stack.push(k, types.getFieldValue(oldNode, k));
- var canReprint = findAnyReprints(newPath, oldPath, reprints);
- newPath.stack.length -= 2;
- oldPath.stack.length -= 2;
- if (!canReprint) {
- return false;
- }
- }
- // Return statements might end up running into ASI issues due to
- // comments inserted deep within the tree, so reprint them if anything
- // changed within them.
- if (ReturnStatement.check(newPath.getNode()) &&
- reprints.length > originalReprintCount) {
- return false;
- }
- return true;
- }
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