如何访问 LESS 生成的 AST？

Question

我想通过访问 AST. The programmatic usage 文档对 LESS 样式表执行一些代码分析，仅涵盖如何呈现文件或字符串。

如何访问 less.js AST？

Answer 1

Github user Vecerek had a similar need。 less.parse 可以与回调一起使用来访问 AST:

...I'm putting the actual code here, that works to get the AST, in case someone will be facing the same hurdle and comes across this issue.
var less = require('less')
  , fs = require('fs')
  , path = require('path');

var src = './test_import.less'; //some less source file
var result = less.parse(fs.readFileSync(src).toString(), {
  filename: path.resolve(src)
}, function(e, tree) {
  console.log(JSON.stringify(tree, null, 2));
});

这段代码可以合理地改编为使用 promise 结构，我发现它更有用：

function lessAST(filename, options) {
    options = options || {};
    options.filename = path.resolve(filename);
    return new Promise(function (res, rej) {
        less.parse(fs.readFileSync(filename).toString(), options, function (e, tree) {
            if (e) {
                rej(e);
            } else {
                res(tree);
            }
        });
    });
}

用法示例：

lessAST('styles.less', {
    ...options...
}).then(function (tree) {
    ...do stuff with the AST...
});

如何访问 LESS 生成的 AST？

How can I access the AST that LESS generates?

abstract-syntax-tree

less

node.js