pgparser

node-pgparser

Parse PostgreSQL statements in Javascript!

pgparser is basically just lib_pgquery ported to Javascript using Emscripten, with a tiny bit of glue! It is a direct port of PostgreSQL's query parser. The output format is a JSON representation of the parse tree.

Note that this is very similar to pg-query-parser. It has the advantage of being plain JS, so it should run fine in browsers (although it's quite large). The drawback of this package is that I haven't implemented a way to transform the parse tree back into SQL (yet!).

Usage

Currently, pgparser simply parses queries into a parse tree. It returns a Promise when invoked:

const pgparser = require('pgparser');
 
let sql = `
    SELECT
        id,
        first_name
    FROM
        users
`;
 
pgparser.parse(sql).then((parse_tree) => {
    console.log(parse_tree);
}, (error) => {
    console.warn(`${error.message} near character ${error.cursorpos}`);
});

The parse tree for the sample query is below:

[
  {
    "SelectStmt": {
      "targetList": [
        {
          "ResTarget": {
            "val": {
              "ColumnRef": {
                "fields": [
                  {
                    "String": {
                      "str": "id"
                    }
                  }
                ],
                "location": 19
              }
            },
            "location": 19
          }
        },
        {
          "ResTarget": {
            "val": {
              "ColumnRef": {
                "fields": [
                  {
                    "String": {
                      "str": "first_name"
                    }
                  }
                ],
                "location": 31
              }
            },
            "location": 31
          }
        }
      ],
      "fromClause": [
        {
          "RangeVar": {
            "relname": "users",
            "inhOpt": 2,
            "relpersistence": "p",
            "location": 59
          }
        }
      ],
      "op": 0
    }
  }
]