com.google.javascript.jscomp

Class RewritePolyfills

java.lang.Object

com.google.javascript.jscomp.RewritePolyfills

All Implemented Interfaces:

CompilerPass, HotSwapCompilerPass

public class RewritePolyfills
extends java.lang.Object
implements HotSwapCompilerPass

Injects polyfill libraries to ensure that ES6+ library functions are available.

Also runs if polyfill isolation is enabled, even if polyfill injection is disabled, in order to prevent deletion of a required library function by dead code elimination.

TODO(b/120486392): consider merging this pass with InjectRuntimeLibraries and InjectTranspilationRuntimeLibraries.

Constructor Summary

Constructors

Constructor and Description
RewritePolyfills(AbstractCompiler compiler, boolean injectPolyfills, boolean isolatePolyfills)

Method Summary

Modifier and Type	Method and Description
void	hotSwapScript(Node scriptRoot, Node originalRoot) Process the JS with root node root.
void	process(Node externs, Node root) Process the JS with root node root.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RewritePolyfills

public RewritePolyfills(AbstractCompiler compiler,
                        boolean injectPolyfills,
                        boolean isolatePolyfills)

Parameters:

injectPolyfills - if true, injects $jscomp.polyfill initializations into the first input. if false, no polyfills are injected.

isolatePolyfills - if true, adds externs for library functions used by IsolatePolyfills to prevent their deletion.

Method Detail

hotSwapScript

public void hotSwapScript(Node scriptRoot,
                          Node originalRoot)

Description copied from interface: HotSwapCompilerPass

Process the JS with root node root. This is supposed to be significantly faster compared to corresponding full-compiler passes.

Specified by:

hotSwapScript in interface HotSwapCompilerPass

Parameters:

scriptRoot - Root node corresponding to the file that is modified, should be of type Token.SCRIPT.

originalRoot - Root node corresponding to the original version of the file that is modified. Should be of type token.SCRIPT.

process

public void process(Node externs,
                    Node root)

Description copied from interface: CompilerPass

Process the JS with root node root. Can modify the contents of each Node tree

Specified by:

process in interface CompilerPass

Parameters:

externs - Top of external JS tree

root - Top of JS tree