factor out compressor/index into more files

lib/ast.js

@@ -41,8 +41,6 @@
 
  ***********************************************************************/
 
-"use strict";
-
 import {
     HOP,
     MAP,

lib/compress/common.js

@@ -0,0 +1,296 @@
+/***********************************************************************
+
+  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 {
+    AST_Array,
+    AST_Arrow,
+    AST_BlockStatement,
+    AST_Call,
+    AST_Class,
+    AST_Const,
+    AST_Constant,
+    AST_DefClass,
+    AST_Defun,
+    AST_EmptyStatement,
+    AST_Export,
+    AST_False,
+    AST_Function,
+    AST_Import,
+    AST_Infinity,
+    AST_LabeledStatement,
+    AST_Lambda,
+    AST_Let,
+    AST_LoopControl,
+    AST_NaN,
+    AST_Node,
+    AST_Null,
+    AST_Number,
+    AST_Object,
+    AST_ObjectKeyVal,
+    AST_PropAccess,
+    AST_RegExp,
+    AST_Scope,
+    AST_Sequence,
+    AST_SimpleStatement,
+    AST_Statement,
+    AST_String,
+    AST_SymbolRef,
+    AST_True,
+    AST_UnaryPrefix,
+    AST_Undefined,
+
+    TreeWalker,
+} from "../ast.js";
+import { make_node, regexp_source_fix, string_template, makePredicate } from "../utils/index.js";
+import { first_in_statement } from "../utils/first_in_statement.js";
+
+export function merge_sequence(array, node) {
+    if (node instanceof AST_Sequence) {
+        array.push(...node.expressions);
+    } else {
+        array.push(node);
+    }
+    return array;
+}
+
+export function make_sequence(orig, expressions) {
+    if (expressions.length == 1) return expressions[0];
+    if (expressions.length == 0) throw new Error("trying to create a sequence with length zero!");
+    return make_node(AST_Sequence, orig, {
+        expressions: expressions.reduce(merge_sequence, [])
+    });
+}
+
+export function make_node_from_constant(val, orig) {
+    switch (typeof val) {
+      case "string":
+        return make_node(AST_String, orig, {
+            value: val
+        });
+      case "number":
+        if (isNaN(val)) return make_node(AST_NaN, orig);
+        if (isFinite(val)) {
+            return 1 / val < 0 ? make_node(AST_UnaryPrefix, orig, {
+                operator: "-",
+                expression: make_node(AST_Number, orig, { value: -val })
+            }) : make_node(AST_Number, orig, { value: val });
+        }
+        return val < 0 ? make_node(AST_UnaryPrefix, orig, {
+            operator: "-",
+            expression: make_node(AST_Infinity, orig)
+        }) : make_node(AST_Infinity, orig);
+      case "boolean":
+        return make_node(val ? AST_True : AST_False, orig);
+      case "undefined":
+        return make_node(AST_Undefined, orig);
+      default:
+        if (val === null) {
+            return make_node(AST_Null, orig, { value: null });
+        }
+        if (val instanceof RegExp) {
+            return make_node(AST_RegExp, orig, {
+                value: {
+                    source: regexp_source_fix(val.source),
+                    flags: val.flags
+                }
+            });
+        }
+        throw new Error(string_template("Can't handle constant of type: {type}", {
+            type: typeof val
+        }));
+    }
+}
+
+export function best_of_expression(ast1, ast2) {
+    return ast1.size() > ast2.size() ? ast2 : ast1;
+}
+
+export function best_of_statement(ast1, ast2) {
+    return best_of_expression(
+        make_node(AST_SimpleStatement, ast1, {
+            body: ast1
+        }),
+        make_node(AST_SimpleStatement, ast2, {
+            body: ast2
+        })
+    ).body;
+}
+
+/** Find which node is smaller, and return that */
+export function best_of(compressor, ast1, ast2) {
+    if (first_in_statement(compressor)) {
+        return best_of_statement(ast1, ast2);
+    } else {
+        return best_of_expression(ast1, ast2);
+    }
+}
+
+/** Simplify an object property's key, if possible */
+export function get_simple_key(key) {
+    if (key instanceof AST_Constant) {
+        return key.getValue();
+    }
+    if (key instanceof AST_UnaryPrefix
+        && key.operator == "void"
+        && key.expression instanceof AST_Constant) {
+        return;
+    }
+    return key;
+}
+
+export function read_property(obj, key) {
+    key = get_simple_key(key);
+    if (key instanceof AST_Node) return;
+
+    var value;
+    if (obj instanceof AST_Array) {
+        var elements = obj.elements;
+        if (key == "length") return make_node_from_constant(elements.length, obj);
+        if (typeof key == "number" && key in elements) value = elements[key];
+    } else if (obj instanceof AST_Object) {
+        key = "" + key;
+        var props = obj.properties;
+        for (var i = props.length; --i >= 0;) {
+            var prop = props[i];
+            if (!(prop instanceof AST_ObjectKeyVal)) return;
+            if (!value && props[i].key === key) value = props[i].value;
+        }
+    }
+
+    return value instanceof AST_SymbolRef && value.fixed_value() || value;
+}
+
+export function has_break_or_continue(loop, parent) {
+    var found = false;
+    var tw = new TreeWalker(function(node) {
+        if (found || node instanceof AST_Scope) return true;
+        if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === loop) {
+            return found = true;
+        }
+    });
+    if (parent instanceof AST_LabeledStatement) tw.push(parent);
+    tw.push(loop);
+    loop.body.walk(tw);
+    return found;
+}
+
+// we shouldn't compress (1,func)(something) to
+// func(something) because that changes the meaning of
+// the func (becomes lexical instead of global).
+export function maintain_this_binding(parent, orig, val) {
+    if (
+        parent instanceof AST_UnaryPrefix && parent.operator == "delete"
+        || parent instanceof AST_Call && parent.expression === orig
+            && (
+                val instanceof AST_PropAccess
+                || val instanceof AST_SymbolRef && val.name == "eval"
+            )
+    ) {
+        const zero = make_node(AST_Number, orig, { value: 0 });
+        return make_sequence(orig, [ zero, val ]);
+    } else {
+        return val;
+    }
+}
+
+export function is_func_expr(node) {
+    return node instanceof AST_Arrow || node instanceof AST_Function;
+}
+
+export function is_iife_call(node) {
+    // Used to determine whether the node can benefit from negation.
+    // Not the case with arrow functions (you need an extra set of parens).
+    if (node.TYPE != "Call") return false;
+    return node.expression instanceof AST_Function || is_iife_call(node.expression);
+}
+
+export const identifier_atom = makePredicate("Infinity NaN undefined");
+export function is_identifier_atom(node) {
+    return node instanceof AST_Infinity
+        || node instanceof AST_NaN
+        || node instanceof AST_Undefined;
+}
+
+/** Check if this is a SymbolRef node which has one def of a certain AST type */
+export function is_ref_of(ref, type) {
+    if (!(ref instanceof AST_SymbolRef)) return false;
+    var orig = ref.definition().orig;
+    for (var i = orig.length; --i >= 0;) {
+        if (orig[i] instanceof type) return true;
+    }
+}
+
+// Can we turn { block contents... } into just the block contents ?
+// Not if one of these is inside.
+export function can_be_evicted_from_block(node) {
+    return !(
+        node instanceof AST_DefClass ||
+        node instanceof AST_Defun ||
+        node instanceof AST_Let ||
+        node instanceof AST_Const ||
+        node instanceof AST_Export ||
+        node instanceof AST_Import
+    );
+}
+
+export function as_statement_array(thing) {
+    if (thing === null) return [];
+    if (thing instanceof AST_BlockStatement) return thing.body;
+    if (thing instanceof AST_EmptyStatement) return [];
+    if (thing instanceof AST_Statement) return [ thing ];
+    throw new Error("Can't convert thing to statement array");
+}
+
+/** Check if a ref refers to the name of a function/class it's defined within */
+export function is_recursive_ref(compressor, def) {
+    var node;
+    for (var i = 0; node = compressor.parent(i); i++) {
+        if (node instanceof AST_Lambda || node instanceof AST_Class) {
+            var name = node.name;
+            if (name && name.definition() === def) {
+                return true;
+            }
+        }
+    }
+    return false;
+}

lib/compress/compressor-flags.js

@@ -0,0 +1,63 @@
+/***********************************************************************
+
+  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.
+
+ ***********************************************************************/
+
+// bitfield flags to be stored in node.flags.
+// These are set and unset during compression, and store information in the node without requiring multiple fields.
+export const UNUSED = 0b00000001;
+export const TRUTHY = 0b00000010;
+export const FALSY = 0b00000100;
+export const UNDEFINED = 0b00001000;
+export const INLINED = 0b00010000;
+
+// Nodes to which values are ever written. Used when keep_assign is part of the unused option string.
+export const WRITE_ONLY = 0b00100000;
+
+// information specific to a single compression pass
+export const SQUEEZED = 0b0000000100000000;
+export const OPTIMIZED = 0b0000001000000000;
+export const TOP = 0b0000010000000000;
+export const CLEAR_BETWEEN_PASSES = SQUEEZED | OPTIMIZED | TOP;
+
+export const has_flag = (node, flag) => node.flags & flag;
+export const set_flag = (node, flag) => { node.flags |= flag; };
+export const clear_flag = (node, flag) => { node.flags &= ~flag; };