ast-types
Version:
Esprima-compatible implementation of the Mozilla JS Parser API
781 lines (780 loc) • 31.7 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Def = void 0;
var tslib_1 = require("tslib");
var Op = Object.prototype;
var objToStr = Op.toString;
var hasOwn = Op.hasOwnProperty;
var BaseType = /** @class */ (function () {
function BaseType() {
}
BaseType.prototype.assert = function (value, deep) {
if (!this.check(value, deep)) {
var str = shallowStringify(value);
throw new Error(str + " does not match type " + this);
}
return true;
};
BaseType.prototype.arrayOf = function () {
var elemType = this;
return new ArrayType(elemType);
};
return BaseType;
}());
var ArrayType = /** @class */ (function (_super) {
tslib_1.__extends(ArrayType, _super);
function ArrayType(elemType) {
var _this = _super.call(this) || this;
_this.elemType = elemType;
_this.kind = "ArrayType";
return _this;
}
ArrayType.prototype.toString = function () {
return "[" + this.elemType + "]";
};
ArrayType.prototype.check = function (value, deep) {
var _this = this;
return Array.isArray(value) && value.every(function (elem) { return _this.elemType.check(elem, deep); });
};
return ArrayType;
}(BaseType));
var IdentityType = /** @class */ (function (_super) {
tslib_1.__extends(IdentityType, _super);
function IdentityType(value) {
var _this = _super.call(this) || this;
_this.value = value;
_this.kind = "IdentityType";
return _this;
}
IdentityType.prototype.toString = function () {
return String(this.value);
};
IdentityType.prototype.check = function (value, deep) {
var result = value === this.value;
if (!result && typeof deep === "function") {
deep(this, value);
}
return result;
};
return IdentityType;
}(BaseType));
var ObjectType = /** @class */ (function (_super) {
tslib_1.__extends(ObjectType, _super);
function ObjectType(fields) {
var _this = _super.call(this) || this;
_this.fields = fields;
_this.kind = "ObjectType";
return _this;
}
ObjectType.prototype.toString = function () {
return "{ " + this.fields.join(", ") + " }";
};
ObjectType.prototype.check = function (value, deep) {
return (objToStr.call(value) === objToStr.call({}) &&
this.fields.every(function (field) {
return field.type.check(value[field.name], deep);
}));
};
return ObjectType;
}(BaseType));
var OrType = /** @class */ (function (_super) {
tslib_1.__extends(OrType, _super);
function OrType(types) {
var _this = _super.call(this) || this;
_this.types = types;
_this.kind = "OrType";
return _this;
}
OrType.prototype.toString = function () {
return this.types.join(" | ");
};
OrType.prototype.check = function (value, deep) {
return this.types.some(function (type) {
return type.check(value, deep);
});
};
return OrType;
}(BaseType));
var PredicateType = /** @class */ (function (_super) {
tslib_1.__extends(PredicateType, _super);
function PredicateType(name, predicate) {
var _this = _super.call(this) || this;
_this.name = name;
_this.predicate = predicate;
_this.kind = "PredicateType";
return _this;
}
PredicateType.prototype.toString = function () {
return this.name;
};
PredicateType.prototype.check = function (value, deep) {
var result = this.predicate(value, deep);
if (!result && typeof deep === "function") {
deep(this, value);
}
return result;
};
return PredicateType;
}(BaseType));
var Def = /** @class */ (function () {
function Def(type, typeName) {
this.type = type;
this.typeName = typeName;
this.baseNames = [];
this.ownFields = Object.create(null);
// Includes own typeName. Populated during finalization.
this.allSupertypes = Object.create(null);
// Linear inheritance hierarchy. Populated during finalization.
this.supertypeList = [];
// Includes inherited fields.
this.allFields = Object.create(null);
// Non-hidden keys of allFields.
this.fieldNames = [];
// This property will be overridden as true by individual Def instances
// when they are finalized.
this.finalized = false;
// False by default until .build(...) is called on an instance.
this.buildable = false;
this.buildParams = [];
}
Def.prototype.isSupertypeOf = function (that) {
if (that instanceof Def) {
if (this.finalized !== true ||
that.finalized !== true) {
throw new Error("");
}
return hasOwn.call(that.allSupertypes, this.typeName);
}
else {
throw new Error(that + " is not a Def");
}
};
Def.prototype.checkAllFields = function (value, deep) {
var allFields = this.allFields;
if (this.finalized !== true) {
throw new Error("" + this.typeName);
}
function checkFieldByName(name) {
var field = allFields[name];
var type = field.type;
var child = field.getValue(value);
return type.check(child, deep);
}
return value !== null &&
typeof value === "object" &&
Object.keys(allFields).every(checkFieldByName);
};
Def.prototype.bases = function () {
var supertypeNames = [];
for (var _i = 0; _i < arguments.length; _i++) {
supertypeNames[_i] = arguments[_i];
}
var bases = this.baseNames;
if (this.finalized) {
if (supertypeNames.length !== bases.length) {
throw new Error("");
}
for (var i = 0; i < supertypeNames.length; i++) {
if (supertypeNames[i] !== bases[i]) {
throw new Error("");
}
}
return this;
}
supertypeNames.forEach(function (baseName) {
// This indexOf lookup may be O(n), but the typical number of base
// names is very small, and indexOf is a native Array method.
if (bases.indexOf(baseName) < 0) {
bases.push(baseName);
}
});
return this; // For chaining.
};
return Def;
}());
exports.Def = Def;
var Field = /** @class */ (function () {
function Field(name, type, defaultFn, hidden) {
this.name = name;
this.type = type;
this.defaultFn = defaultFn;
this.hidden = !!hidden;
}
Field.prototype.toString = function () {
return JSON.stringify(this.name) + ": " + this.type;
};
Field.prototype.getValue = function (obj) {
var value = obj[this.name];
if (typeof value !== "undefined") {
return value;
}
if (typeof this.defaultFn === "function") {
value = this.defaultFn.call(obj);
}
return value;
};
return Field;
}());
function shallowStringify(value) {
if (Array.isArray(value)) {
return "[" + value.map(shallowStringify).join(", ") + "]";
}
if (value && typeof value === "object") {
return "{ " + Object.keys(value).map(function (key) {
return key + ": " + value[key];
}).join(", ") + " }";
}
return JSON.stringify(value);
}
function typesPlugin(_fork) {
var Type = {
or: function () {
var types = [];
for (var _i = 0; _i < arguments.length; _i++) {
types[_i] = arguments[_i];
}
return new OrType(types.map(function (type) { return Type.from(type); }));
},
from: function (value, name) {
if (value instanceof ArrayType ||
value instanceof IdentityType ||
value instanceof ObjectType ||
value instanceof OrType ||
value instanceof PredicateType) {
return value;
}
// The Def type is used as a helper for constructing compound
// interface types for AST nodes.
if (value instanceof Def) {
return value.type;
}
// Support [ElemType] syntax.
if (isArray.check(value)) {
if (value.length !== 1) {
throw new Error("only one element type is permitted for typed arrays");
}
return new ArrayType(Type.from(value[0]));
}
// Support { someField: FieldType, ... } syntax.
if (isObject.check(value)) {
return new ObjectType(Object.keys(value).map(function (name) {
return new Field(name, Type.from(value[name], name));
}));
}
if (typeof value === "function") {
var bicfIndex = builtInCtorFns.indexOf(value);
if (bicfIndex >= 0) {
return builtInCtorTypes[bicfIndex];
}
if (typeof name !== "string") {
throw new Error("missing name");
}
return new PredicateType(name, value);
}
// As a last resort, toType returns a type that matches any value that
// is === from. This is primarily useful for literal values like
// toType(null), but it has the additional advantage of allowing
// toType to be a total function.
return new IdentityType(value);
},
// Define a type whose name is registered in a namespace (the defCache) so
// that future definitions will return the same type given the same name.
// In particular, this system allows for circular and forward definitions.
// The Def object d returned from Type.def may be used to configure the
// type d.type by calling methods such as d.bases, d.build, and d.field.
def: function (typeName) {
return hasOwn.call(defCache, typeName)
? defCache[typeName]
: defCache[typeName] = new DefImpl(typeName);
},
hasDef: function (typeName) {
return hasOwn.call(defCache, typeName);
}
};
var builtInCtorFns = [];
var builtInCtorTypes = [];
function defBuiltInType(name, example) {
var objStr = objToStr.call(example);
var type = new PredicateType(name, function (value) { return objToStr.call(value) === objStr; });
if (example && typeof example.constructor === "function") {
builtInCtorFns.push(example.constructor);
builtInCtorTypes.push(type);
}
return type;
}
// These types check the underlying [[Class]] attribute of the given
// value, rather than using the problematic typeof operator. Note however
// that no subtyping is considered; so, for instance, isObject.check
// returns false for [], /./, new Date, and null.
var isString = defBuiltInType("string", "truthy");
var isFunction = defBuiltInType("function", function () { });
var isArray = defBuiltInType("array", []);
var isObject = defBuiltInType("object", {});
var isRegExp = defBuiltInType("RegExp", /./);
var isDate = defBuiltInType("Date", new Date());
var isNumber = defBuiltInType("number", 3);
var isBoolean = defBuiltInType("boolean", true);
var isNull = defBuiltInType("null", null);
var isUndefined = defBuiltInType("undefined", undefined);
var builtInTypes = {
string: isString,
function: isFunction,
array: isArray,
object: isObject,
RegExp: isRegExp,
Date: isDate,
number: isNumber,
boolean: isBoolean,
null: isNull,
undefined: isUndefined,
};
// In order to return the same Def instance every time Type.def is called
// with a particular name, those instances need to be stored in a cache.
var defCache = Object.create(null);
function defFromValue(value) {
if (value && typeof value === "object") {
var type = value.type;
if (typeof type === "string" &&
hasOwn.call(defCache, type)) {
var d = defCache[type];
if (d.finalized) {
return d;
}
}
}
return null;
}
var DefImpl = /** @class */ (function (_super) {
tslib_1.__extends(DefImpl, _super);
function DefImpl(typeName) {
var _this = _super.call(this, new PredicateType(typeName, function (value, deep) { return _this.check(value, deep); }), typeName) || this;
return _this;
}
DefImpl.prototype.check = function (value, deep) {
if (this.finalized !== true) {
throw new Error("prematurely checking unfinalized type " + this.typeName);
}
// A Def type can only match an object value.
if (value === null || typeof value !== "object") {
return false;
}
var vDef = defFromValue(value);
if (!vDef) {
// If we couldn't infer the Def associated with the given value,
// and we expected it to be a SourceLocation or a Position, it was
// probably just missing a "type" field (because Esprima does not
// assign a type property to such nodes). Be optimistic and let
// this.checkAllFields make the final decision.
if (this.typeName === "SourceLocation" ||
this.typeName === "Position") {
return this.checkAllFields(value, deep);
}
// Calling this.checkAllFields for any other type of node is both
// bad for performance and way too forgiving.
return false;
}
// If checking deeply and vDef === this, then we only need to call
// checkAllFields once. Calling checkAllFields is too strict when deep
// is false, because then we only care about this.isSupertypeOf(vDef).
if (deep && vDef === this) {
return this.checkAllFields(value, deep);
}
// In most cases we rely exclusively on isSupertypeOf to make O(1)
// subtyping determinations. This suffices in most situations outside
// of unit tests, since interface conformance is checked whenever new
// instances are created using builder functions.
if (!this.isSupertypeOf(vDef)) {
return false;
}
// The exception is when deep is true; then, we recursively check all
// fields.
if (!deep) {
return true;
}
// Use the more specific Def (vDef) to perform the deep check, but
// shallow-check fields defined by the less specific Def (this).
return vDef.checkAllFields(value, deep)
&& this.checkAllFields(value, false);
};
DefImpl.prototype.build = function () {
var _this = this;
var buildParams = [];
for (var _i = 0; _i < arguments.length; _i++) {
buildParams[_i] = arguments[_i];
}
// Calling Def.prototype.build multiple times has the effect of merely
// redefining this property.
this.buildParams = buildParams;
if (this.buildable) {
// If this Def is already buildable, update self.buildParams and
// continue using the old builder function.
return this;
}
// Every buildable type will have its "type" field filled in
// automatically. This includes types that are not subtypes of Node,
// like SourceLocation, but that seems harmless (TODO?).
this.field("type", String, function () { return _this.typeName; });
// Override Dp.buildable for this Def instance.
this.buildable = true;
var addParam = function (built, param, arg, isArgAvailable) {
if (hasOwn.call(built, param))
return;
var all = _this.allFields;
if (!hasOwn.call(all, param)) {
throw new Error("" + param);
}
var field = all[param];
var type = field.type;
var value;
if (isArgAvailable) {
value = arg;
}
else if (field.defaultFn) {
// Expose the partially-built object to the default
// function as its `this` object.
value = field.defaultFn.call(built);
}
else {
var message = "no value or default function given for field " +
JSON.stringify(param) + " of " + _this.typeName + "(" +
_this.buildParams.map(function (name) {
return all[name];
}).join(", ") + ")";
throw new Error(message);
}
if (!type.check(value)) {
throw new Error(shallowStringify(value) +
" does not match field " + field +
" of type " + _this.typeName);
}
built[param] = value;
};
// Calling the builder function will construct an instance of the Def,
// with positional arguments mapped to the fields original passed to .build.
// If not enough arguments are provided, the default value for the remaining fields
// will be used.
var builder = function () {
var args = [];
for (var _i = 0; _i < arguments.length; _i++) {
args[_i] = arguments[_i];
}
var argc = args.length;
if (!_this.finalized) {
throw new Error("attempting to instantiate unfinalized type " +
_this.typeName);
}
var built = Object.create(nodePrototype);
_this.buildParams.forEach(function (param, i) {
if (i < argc) {
addParam(built, param, args[i], true);
}
else {
addParam(built, param, null, false);
}
});
Object.keys(_this.allFields).forEach(function (param) {
// Use the default value.
addParam(built, param, null, false);
});
// Make sure that the "type" field was filled automatically.
if (built.type !== _this.typeName) {
throw new Error("");
}
return built;
};
// Calling .from on the builder function will construct an instance of the Def,
// using field values from the passed object. For fields missing from the passed object,
// their default value will be used.
builder.from = function (obj) {
if (!_this.finalized) {
throw new Error("attempting to instantiate unfinalized type " +
_this.typeName);
}
var built = Object.create(nodePrototype);
Object.keys(_this.allFields).forEach(function (param) {
if (hasOwn.call(obj, param)) {
addParam(built, param, obj[param], true);
}
else {
addParam(built, param, null, false);
}
});
// Make sure that the "type" field was filled automatically.
if (built.type !== _this.typeName) {
throw new Error("");
}
return built;
};
Object.defineProperty(builders, getBuilderName(this.typeName), {
enumerable: true,
value: builder
});
return this;
};
// The reason fields are specified using .field(...) instead of an object
// literal syntax is somewhat subtle: the object literal syntax would
// support only one key and one value, but with .field(...) we can pass
// any number of arguments to specify the field.
DefImpl.prototype.field = function (name, type, defaultFn, hidden) {
if (this.finalized) {
console.error("Ignoring attempt to redefine field " +
JSON.stringify(name) + " of finalized type " +
JSON.stringify(this.typeName));
return this;
}
this.ownFields[name] = new Field(name, Type.from(type), defaultFn, hidden);
return this; // For chaining.
};
DefImpl.prototype.finalize = function () {
var _this = this;
// It's not an error to finalize a type more than once, but only the
// first call to .finalize does anything.
if (!this.finalized) {
var allFields = this.allFields;
var allSupertypes = this.allSupertypes;
this.baseNames.forEach(function (name) {
var def = defCache[name];
if (def instanceof Def) {
def.finalize();
extend(allFields, def.allFields);
extend(allSupertypes, def.allSupertypes);
}
else {
var message = "unknown supertype name " +
JSON.stringify(name) +
" for subtype " +
JSON.stringify(_this.typeName);
throw new Error(message);
}
});
// TODO Warn if fields are overridden with incompatible types.
extend(allFields, this.ownFields);
allSupertypes[this.typeName] = this;
this.fieldNames.length = 0;
for (var fieldName in allFields) {
if (hasOwn.call(allFields, fieldName) &&
!allFields[fieldName].hidden) {
this.fieldNames.push(fieldName);
}
}
// Types are exported only once they have been finalized.
Object.defineProperty(namedTypes, this.typeName, {
enumerable: true,
value: this.type
});
this.finalized = true;
// A linearization of the inheritance hierarchy.
populateSupertypeList(this.typeName, this.supertypeList);
if (this.buildable &&
this.supertypeList.lastIndexOf("Expression") >= 0) {
wrapExpressionBuilderWithStatement(this.typeName);
}
}
};
return DefImpl;
}(Def));
// Note that the list returned by this function is a copy of the internal
// supertypeList, *without* the typeName itself as the first element.
function getSupertypeNames(typeName) {
if (!hasOwn.call(defCache, typeName)) {
throw new Error("");
}
var d = defCache[typeName];
if (d.finalized !== true) {
throw new Error("");
}
return d.supertypeList.slice(1);
}
// Returns an object mapping from every known type in the defCache to the
// most specific supertype whose name is an own property of the candidates
// object.
function computeSupertypeLookupTable(candidates) {
var table = {};
var typeNames = Object.keys(defCache);
var typeNameCount = typeNames.length;
for (var i = 0; i < typeNameCount; ++i) {
var typeName = typeNames[i];
var d = defCache[typeName];
if (d.finalized !== true) {
throw new Error("" + typeName);
}
for (var j = 0; j < d.supertypeList.length; ++j) {
var superTypeName = d.supertypeList[j];
if (hasOwn.call(candidates, superTypeName)) {
table[typeName] = superTypeName;
break;
}
}
}
return table;
}
var builders = Object.create(null);
// This object is used as prototype for any node created by a builder.
var nodePrototype = {};
// Call this function to define a new method to be shared by all AST
// nodes. The replaced method (if any) is returned for easy wrapping.
function defineMethod(name, func) {
var old = nodePrototype[name];
// Pass undefined as func to delete nodePrototype[name].
if (isUndefined.check(func)) {
delete nodePrototype[name];
}
else {
isFunction.assert(func);
Object.defineProperty(nodePrototype, name, {
enumerable: true,
configurable: true,
value: func
});
}
return old;
}
function getBuilderName(typeName) {
return typeName.replace(/^[A-Z]+/, function (upperCasePrefix) {
var len = upperCasePrefix.length;
switch (len) {
case 0: return "";
// If there's only one initial capital letter, just lower-case it.
case 1: return upperCasePrefix.toLowerCase();
default:
// If there's more than one initial capital letter, lower-case
// all but the last one, so that XMLDefaultDeclaration (for
// example) becomes xmlDefaultDeclaration.
return upperCasePrefix.slice(0, len - 1).toLowerCase() +
upperCasePrefix.charAt(len - 1);
}
});
}
function getStatementBuilderName(typeName) {
typeName = getBuilderName(typeName);
return typeName.replace(/(Expression)?$/, "Statement");
}
var namedTypes = {};
// Like Object.keys, but aware of what fields each AST type should have.
function getFieldNames(object) {
var d = defFromValue(object);
if (d) {
return d.fieldNames.slice(0);
}
if ("type" in object) {
throw new Error("did not recognize object of type " +
JSON.stringify(object.type));
}
return Object.keys(object);
}
// Get the value of an object property, taking object.type and default
// functions into account.
function getFieldValue(object, fieldName) {
var d = defFromValue(object);
if (d) {
var field = d.allFields[fieldName];
if (field) {
return field.getValue(object);
}
}
return object && object[fieldName];
}
// Iterate over all defined fields of an object, including those missing
// or undefined, passing each field name and effective value (as returned
// by getFieldValue) to the callback. If the object has no corresponding
// Def, the callback will never be called.
function eachField(object, callback, context) {
getFieldNames(object).forEach(function (name) {
callback.call(this, name, getFieldValue(object, name));
}, context);
}
// Similar to eachField, except that iteration stops as soon as the
// callback returns a truthy value. Like Array.prototype.some, the final
// result is either true or false to indicates whether the callback
// returned true for any element or not.
function someField(object, callback, context) {
return getFieldNames(object).some(function (name) {
return callback.call(this, name, getFieldValue(object, name));
}, context);
}
// Adds an additional builder for Expression subtypes
// that wraps the built Expression in an ExpressionStatements.
function wrapExpressionBuilderWithStatement(typeName) {
var wrapperName = getStatementBuilderName(typeName);
// skip if the builder already exists
if (builders[wrapperName])
return;
// the builder function to wrap with builders.ExpressionStatement
var wrapped = builders[getBuilderName(typeName)];
// skip if there is nothing to wrap
if (!wrapped)
return;
var builder = function () {
var args = [];
for (var _i = 0; _i < arguments.length; _i++) {
args[_i] = arguments[_i];
}
return builders.expressionStatement(wrapped.apply(builders, args));
};
builder.from = function () {
var args = [];
for (var _i = 0; _i < arguments.length; _i++) {
args[_i] = arguments[_i];
}
return builders.expressionStatement(wrapped.from.apply(builders, args));
};
builders[wrapperName] = builder;
}
function populateSupertypeList(typeName, list) {
list.length = 0;
list.push(typeName);
var lastSeen = Object.create(null);
for (var pos = 0; pos < list.length; ++pos) {
typeName = list[pos];
var d = defCache[typeName];
if (d.finalized !== true) {
throw new Error("");
}
// If we saw typeName earlier in the breadth-first traversal,
// delete the last-seen occurrence.
if (hasOwn.call(lastSeen, typeName)) {
delete list[lastSeen[typeName]];
}
// Record the new index of the last-seen occurrence of typeName.
lastSeen[typeName] = pos;
// Enqueue the base names of this type.
list.push.apply(list, d.baseNames);
}
// Compaction loop to remove array holes.
for (var to = 0, from = to, len = list.length; from < len; ++from) {
if (hasOwn.call(list, from)) {
list[to++] = list[from];
}
}
list.length = to;
}
function extend(into, from) {
Object.keys(from).forEach(function (name) {
into[name] = from[name];
});
return into;
}
function finalize() {
Object.keys(defCache).forEach(function (name) {
defCache[name].finalize();
});
}
return {
Type: Type,
builtInTypes: builtInTypes,
getSupertypeNames: getSupertypeNames,
computeSupertypeLookupTable: computeSupertypeLookupTable,
builders: builders,
defineMethod: defineMethod,
getBuilderName: getBuilderName,
getStatementBuilderName: getStatementBuilderName,
namedTypes: namedTypes,
getFieldNames: getFieldNames,
getFieldValue: getFieldValue,
eachField: eachField,
someField: someField,
finalize: finalize,
};
}
exports.default = typesPlugin;
;