98 lines
3.2 KiB
JavaScript
98 lines
3.2 KiB
JavaScript
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// sample on how to use the parser and walker API to instrument some code
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var jsp = require("uglify-js").parser;
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var pro = require("uglify-js").uglify;
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function instrument(code) {
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var ast = jsp.parse(code, false, true); // true for the third arg specifies that we want
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// to have start/end tokens embedded in the
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// statements
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var w = pro.ast_walker();
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// we're gonna need this to push elements that we're currently looking at, to avoid
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// endless recursion.
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var analyzing = [];
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function do_stat() {
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var ret;
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if (this[0].start && analyzing.indexOf(this) < 0) {
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// without the `analyzing' hack, w.walk(this) would re-enter here leading
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// to infinite recursion
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analyzing.push(this);
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ret = [ "splice", // XXX: "block" is safer
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[ [ "stat",
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[ "call", [ "name", "trace" ],
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[ [ "string", this[0].toString() ],
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[ "num", this[0].start.line ],
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[ "num", this[0].start.col ],
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[ "num", this[0].end.line ],
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[ "num", this[0].end.col ]]]],
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w.walk(this) ]];
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analyzing.pop(this);
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}
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return ret;
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};
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var new_ast = w.with_walkers({
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"stat" : do_stat,
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"label" : do_stat,
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"break" : do_stat,
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"continue" : do_stat,
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"debugger" : do_stat,
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"var" : do_stat,
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"const" : do_stat,
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"return" : do_stat,
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"throw" : do_stat,
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"try" : do_stat,
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"defun" : do_stat,
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"if" : do_stat,
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"while" : do_stat,
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"do" : do_stat,
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"for" : do_stat,
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"for-in" : do_stat,
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"switch" : do_stat,
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"with" : do_stat
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}, function(){
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return w.walk(ast);
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});
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return pro.gen_code(new_ast, { beautify: true });
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}
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////// test code follows.
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var code = instrument(test.toString());
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console.log(code);
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function test() {
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// simple stats
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a = 5;
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c += a + b;
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"foo";
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// var
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var foo = 5;
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const bar = 6, baz = 7;
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// switch block. note we can't track case lines the same way.
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switch ("foo") {
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case "foo":
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return 1;
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case "bar":
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return 2;
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}
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// for/for in
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for (var i = 0; i < 5; ++i) {
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console.log("Hello " + i);
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}
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for (var i in [ 1, 2, 3]) {
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console.log(i);
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}
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// note however that the following is broken. I guess we
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// should add the block brackets in this case...
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for (var i = 0; i < 5; ++i)
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console.log("foo");
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}
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