diff options
| author | littleblack111 <littleblack11111@gmail.com> | 2023-11-05 17:16:09 +0800 |
|---|---|---|
| committer | littleblack111 <littleblack11111@gmail.com> | 2023-11-05 17:16:09 +0800 |
| commit | d1d9f00b1bd660842addf5e6b1d1b64c852a9eea (patch) | |
| tree | 60fb37ae73a1109d95301de5ec9b61b5726a4b61 /node_modules/terser/lib/compress/evaluate.js | |
| parent | 7c85166c4cbdd862fc4252007d2df5befcbc2a58 (diff) | |
added hover prefixer
Diffstat (limited to 'node_modules/terser/lib/compress/evaluate.js')
| -rw-r--r-- | node_modules/terser/lib/compress/evaluate.js | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/node_modules/terser/lib/compress/evaluate.js b/node_modules/terser/lib/compress/evaluate.js new file mode 100644 index 00000000..d249ee35 --- /dev/null +++ b/node_modules/terser/lib/compress/evaluate.js @@ -0,0 +1,488 @@ +/*********************************************************************** + + A JavaScript tokenizer / parser / beautifier / compressor. + https://github.com/mishoo/UglifyJS2 + + -------------------------------- (C) --------------------------------- + + Author: Mihai Bazon + <mihai.bazon@gmail.com> + http://mihai.bazon.net/blog + + Distributed under the BSD license: + + Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com> + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above + copyright notice, this list of conditions and the following + disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials + provided with the distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY + EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, + OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR + TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF + THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + SUCH DAMAGE. + + ***********************************************************************/ + +import { + HOP, + makePredicate, + return_this, + string_template, + regexp_source_fix, + regexp_is_safe, +} from "../utils/index.js"; +import { + AST_Array, + AST_BigInt, + AST_Binary, + AST_Call, + AST_Chain, + AST_Class, + AST_Conditional, + AST_Constant, + AST_Dot, + AST_Expansion, + AST_Function, + AST_Lambda, + AST_New, + AST_Node, + AST_Object, + AST_PropAccess, + AST_RegExp, + AST_Statement, + AST_Symbol, + AST_SymbolRef, + AST_TemplateString, + AST_UnaryPrefix, + AST_With, +} from "../ast.js"; +import { is_undeclared_ref} from "./inference.js"; +import { is_pure_native_value, is_pure_native_fn, is_pure_native_method } from "./native-objects.js"; + +// methods to evaluate a constant expression + +function def_eval(node, func) { + node.DEFMETHOD("_eval", func); +} + +// Used to propagate a nullish short-circuit signal upwards through the chain. +export const nullish = Symbol("This AST_Chain is nullish"); + +// If the node has been successfully reduced to a constant, +// then its value is returned; otherwise the element itself +// is returned. +// They can be distinguished as constant value is never a +// descendant of AST_Node. +AST_Node.DEFMETHOD("evaluate", function (compressor) { + if (!compressor.option("evaluate")) + return this; + var val = this._eval(compressor, 1); + if (!val || val instanceof RegExp) + return val; + if (typeof val == "function" || typeof val == "object" || val == nullish) + return this; + + // Evaluated strings can be larger than the original expression + if (typeof val === "string") { + const unevaluated_size = this.size(compressor); + if (val.length + 2 > unevaluated_size) return this; + } + + return val; +}); + +var unaryPrefix = makePredicate("! ~ - + void"); +AST_Node.DEFMETHOD("is_constant", function () { + // Accomodate when compress option evaluate=false + // as well as the common constant expressions !0 and -1 + if (this instanceof AST_Constant) { + return !(this instanceof AST_RegExp); + } else { + return this instanceof AST_UnaryPrefix + && this.expression instanceof AST_Constant + && unaryPrefix.has(this.operator); + } +}); + +def_eval(AST_Statement, function () { + throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start)); +}); + +def_eval(AST_Lambda, return_this); +def_eval(AST_Class, return_this); +def_eval(AST_Node, return_this); +def_eval(AST_Constant, function () { + return this.getValue(); +}); + +def_eval(AST_BigInt, return_this); + +def_eval(AST_RegExp, function (compressor) { + let evaluated = compressor.evaluated_regexps.get(this.value); + if (evaluated === undefined && regexp_is_safe(this.value.source)) { + try { + const { source, flags } = this.value; + evaluated = new RegExp(source, flags); + } catch (e) { + evaluated = null; + } + compressor.evaluated_regexps.set(this.value, evaluated); + } + return evaluated || this; +}); + +def_eval(AST_TemplateString, function () { + if (this.segments.length !== 1) return this; + return this.segments[0].value; +}); + +def_eval(AST_Function, function (compressor) { + if (compressor.option("unsafe")) { + var fn = function () { }; + fn.node = this; + fn.toString = () => this.print_to_string(); + return fn; + } + return this; +}); + +def_eval(AST_Array, function (compressor, depth) { + if (compressor.option("unsafe")) { + var elements = []; + for (var i = 0, len = this.elements.length; i < len; i++) { + var element = this.elements[i]; + var value = element._eval(compressor, depth); + if (element === value) + return this; + elements.push(value); + } + return elements; + } + return this; +}); + +def_eval(AST_Object, function (compressor, depth) { + if (compressor.option("unsafe")) { + var val = {}; + for (var i = 0, len = this.properties.length; i < len; i++) { + var prop = this.properties[i]; + if (prop instanceof AST_Expansion) + return this; + var key = prop.key; + if (key instanceof AST_Symbol) { + key = key.name; + } else if (key instanceof AST_Node) { + key = key._eval(compressor, depth); + if (key === prop.key) + return this; + } + if (typeof Object.prototype[key] === "function") { + return this; + } + if (prop.value instanceof AST_Function) + continue; + val[key] = prop.value._eval(compressor, depth); + if (val[key] === prop.value) + return this; + } + return val; + } + return this; +}); + +var non_converting_unary = makePredicate("! typeof void"); +def_eval(AST_UnaryPrefix, function (compressor, depth) { + var e = this.expression; + // Function would be evaluated to an array and so typeof would + // incorrectly return 'object'. Hence making is a special case. + if (compressor.option("typeofs") + && this.operator == "typeof" + && (e instanceof AST_Lambda + || e instanceof AST_SymbolRef + && e.fixed_value() instanceof AST_Lambda)) { + return typeof function () { }; + } + if (!non_converting_unary.has(this.operator)) + depth++; + e = e._eval(compressor, depth); + if (e === this.expression) + return this; + switch (this.operator) { + case "!": return !e; + case "typeof": + // typeof <RegExp> returns "object" or "function" on different platforms + // so cannot evaluate reliably + if (e instanceof RegExp) + return this; + return typeof e; + case "void": return void e; + case "~": return ~e; + case "-": return -e; + case "+": return +e; + } + return this; +}); + +var non_converting_binary = makePredicate("&& || ?? === !=="); +const identity_comparison = makePredicate("== != === !=="); +const has_identity = value => typeof value === "object" + || typeof value === "function" + || typeof value === "symbol"; + +def_eval(AST_Binary, function (compressor, depth) { + if (!non_converting_binary.has(this.operator)) + depth++; + + var left = this.left._eval(compressor, depth); + if (left === this.left) + return this; + var right = this.right._eval(compressor, depth); + if (right === this.right) + return this; + var result; + + if (left != null + && right != null + && identity_comparison.has(this.operator) + && has_identity(left) + && has_identity(right) + && typeof left === typeof right) { + // Do not compare by reference + return this; + } + + switch (this.operator) { + case "&&": result = left && right; break; + case "||": result = left || right; break; + case "??": result = left != null ? left : right; break; + case "|": result = left | right; break; + case "&": result = left & right; break; + case "^": result = left ^ right; break; + case "+": result = left + right; break; + case "*": result = left * right; break; + case "**": result = Math.pow(left, right); break; + case "/": result = left / right; break; + case "%": result = left % right; break; + case "-": result = left - right; break; + case "<<": result = left << right; break; + case ">>": result = left >> right; break; + case ">>>": result = left >>> right; break; + case "==": result = left == right; break; + case "===": result = left === right; break; + case "!=": result = left != right; break; + case "!==": result = left !== right; break; + case "<": result = left < right; break; + case "<=": result = left <= right; break; + case ">": result = left > right; break; + case ">=": result = left >= right; break; + default: + return this; + } + if (isNaN(result) && compressor.find_parent(AST_With)) { + // leave original expression as is + return this; + } + return result; +}); + +def_eval(AST_Conditional, function (compressor, depth) { + var condition = this.condition._eval(compressor, depth); + if (condition === this.condition) + return this; + var node = condition ? this.consequent : this.alternative; + var value = node._eval(compressor, depth); + return value === node ? this : value; +}); + +// Set of AST_SymbolRef which are currently being evaluated. +// Avoids infinite recursion of ._eval() +const reentrant_ref_eval = new Set(); +def_eval(AST_SymbolRef, function (compressor, depth) { + if (reentrant_ref_eval.has(this)) + return this; + + var fixed = this.fixed_value(); + if (!fixed) + return this; + + reentrant_ref_eval.add(this); + const value = fixed._eval(compressor, depth); + reentrant_ref_eval.delete(this); + + if (value === fixed) + return this; + + if (value && typeof value == "object") { + var escaped = this.definition().escaped; + if (escaped && depth > escaped) + return this; + } + return value; +}); + +const global_objs = { Array, Math, Number, Object, String }; + +const regexp_flags = new Set([ + "dotAll", + "global", + "ignoreCase", + "multiline", + "sticky", + "unicode", +]); + +def_eval(AST_PropAccess, function (compressor, depth) { + let obj = this.expression._eval(compressor, depth + 1); + if (obj === nullish || (this.optional && obj == null)) return nullish; + + // `.length` of strings and arrays is always safe + if (this.property === "length") { + if (typeof obj === "string") { + return obj.length; + } + + const is_spreadless_array = + obj instanceof AST_Array + && obj.elements.every(el => !(el instanceof AST_Expansion)); + + if ( + is_spreadless_array + && obj.elements.every(el => !el.has_side_effects(compressor)) + ) { + return obj.elements.length; + } + } + + if (compressor.option("unsafe")) { + var key = this.property; + if (key instanceof AST_Node) { + key = key._eval(compressor, depth); + if (key === this.property) + return this; + } + + var exp = this.expression; + if (is_undeclared_ref(exp)) { + var aa; + var first_arg = exp.name === "hasOwnProperty" + && key === "call" + && (aa = compressor.parent() && compressor.parent().args) + && (aa && aa[0] + && aa[0].evaluate(compressor)); + + first_arg = first_arg instanceof AST_Dot ? first_arg.expression : first_arg; + + if (first_arg == null || first_arg.thedef && first_arg.thedef.undeclared) { + return this.clone(); + } + if (!is_pure_native_value(exp.name, key)) + return this; + obj = global_objs[exp.name]; + } else { + if (obj instanceof RegExp) { + if (key == "source") { + return regexp_source_fix(obj.source); + } else if (key == "flags" || regexp_flags.has(key)) { + return obj[key]; + } + } + if (!obj || obj === exp || !HOP(obj, key)) + return this; + + if (typeof obj == "function") + switch (key) { + case "name": + return obj.node.name ? obj.node.name.name : ""; + case "length": + return obj.node.length_property(); + default: + return this; + } + } + return obj[key]; + } + return this; +}); + +def_eval(AST_Chain, function (compressor, depth) { + const evaluated = this.expression._eval(compressor, depth); + return evaluated === nullish + ? undefined + : evaluated === this.expression + ? this + : evaluated; +}); + +def_eval(AST_Call, function (compressor, depth) { + var exp = this.expression; + + const callee = exp._eval(compressor, depth); + if (callee === nullish || (this.optional && callee == null)) return nullish; + + if (compressor.option("unsafe") && exp instanceof AST_PropAccess) { + var key = exp.property; + if (key instanceof AST_Node) { + key = key._eval(compressor, depth); + if (key === exp.property) + return this; + } + var val; + var e = exp.expression; + if (is_undeclared_ref(e)) { + var first_arg = e.name === "hasOwnProperty" && + key === "call" && + (this.args[0] && this.args[0].evaluate(compressor)); + + first_arg = first_arg instanceof AST_Dot ? first_arg.expression : first_arg; + + if ((first_arg == null || first_arg.thedef && first_arg.thedef.undeclared)) { + return this.clone(); + } + if (!is_pure_native_fn(e.name, key)) return this; + val = global_objs[e.name]; + } else { + val = e._eval(compressor, depth + 1); + if (val === e || !val) + return this; + if (!is_pure_native_method(val.constructor.name, key)) + return this; + } + var args = []; + for (var i = 0, len = this.args.length; i < len; i++) { + var arg = this.args[i]; + var value = arg._eval(compressor, depth); + if (arg === value) + return this; + if (arg instanceof AST_Lambda) + return this; + args.push(value); + } + try { + return val[key].apply(val, args); + } catch (ex) { + // We don't really care + } + } + return this; +}); + +// Also a subclass of AST_Call +def_eval(AST_New, return_this); |
