ast-plugin/lib/Ast.js

The simplest abstract syntax tree walker.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Ast = void 0;

var _helper = require("./helper");

var _global = require("./global");

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var Ast =
/*#__PURE__*/
function () {
  function Ast(node, parent, text) {
    _classCallCheck(this, Ast);

    this.node = node;
    this.parent = parent; // 文本、代码

    this.text = text;
    this.skiped = false;
  }

  _createClass(Ast, [{
    key: "get",
    value: function get(path) {
      var _this = this;

      var arr = (0, _helper.toPath)(path);
      return arr.reduce(function (value, key) {
        if (value === undefined) return undefined;
        var node = value.node[key];
        return node === undefined ? undefined : new Ast(node, value, _this.text);
      }, this);
    } // 处理 plugin

  }, {
    key: "visit",
    value: function visit(plugins) {
      var _this2 = this;

      var _getGlobalConfig = (0, _global.getGlobalConfig)(),
          typeKey = _getGlobalConfig.typeKey,
          childrenKey = _getGlobalConfig.childrenKey;

      var node = this.node;
      plugins.forEach(function (plugin) {
        // visitor 函数返回的 object
        var visitor = plugin.visitor();
        var keys = Object.keys(visitor);
        keys.forEach(function (key) {
          var v = visitor[key]; // 匹配的时候才处理

          if (node[typeKey] === key) v(_this2);
        });
      });
    }
  }, {
    key: "process",
    value: function process(plugins) {
      var _this3 = this;

      var _getGlobalConfig2 = (0, _global.getGlobalConfig)(),
          typeKey = _getGlobalConfig2.typeKey,
          childrenKey = _getGlobalConfig2.childrenKey;

      var children = this.node[childrenKey]; // 处理当前

      this.visit(plugins); // 处理子元素

      if (Array.isArray(children) && !this.skiped) {
        children.forEach(function (child) {
          return new Ast(child, _this3, _this3.text).process(plugins);
        });
      }
    }
  }, {
    key: "traverse",
    value: function traverse(plugins) {
      // 前置处理
      plugins.forEach(function (plugin) {
        return plugin.pre();
      }); // 遍历

      this.process(plugins); // 后置处理

      plugins.forEach(function (plugin) {
        return plugin.post();
      });
      return this;
    }
  }, {
    key: "skip",
    value: function skip() {
      this.skiped = true;
    }
    /**
     * 获得当前 ast 的文本内容片段
     * @returns {string}
     */

  }, {
    key: "segment",
    value: function segment() {
      var lines = this.text.split('\n');
      var _this$node$position = this.node.position,
          start = _this$node$position.start,
          end = _this$node$position.end;
      var r = [];

      for (var i = start.line; i <= end.line; i++) {
        var line = lines[i - 1];

        if (i === end.line) {
          line = line.substring(0, end.column - 1);
        }

        if (i === start.line) {
          line = line.substring(start.column - 1);
        }

        r.push(line);
      }

      return r.join('\n');
    }
  }]);

  return Ast;
}();

exports.Ast = Ast;