pgsql-minify

A simple typescript library to generate a minified version of a valid Postgres SQL statement.

The minifier works by breaking the raw SQL statement into a collection of 'tokens' using a simple lexical analyzer (lexer), and then reconstructs the statement from the tokens using standardised case and spacing.

Installation

npm install pgsql-minify

Or

yarn add pgsql-minify

Quickstart

Typescript

import { minify } from 'pgsql-minify';
:
const rawSQL = `select col1, col2,\n\tcol3\nFROM\tsome_table;`;
const niceSQL = minify(rawSQL); // select col1, col2, col3 from some_table;

Javascript

const pgmin = require('pgsql-minify')
:
const rawSQL = 'select    abc  from       def   ;   ';
const niceSQL = pgmin.minify(rawSQL); // select abc from def;

API and Components

In addition to the minify function seen above, the package also exposes a number of other components that may be useful if you want to roll your own minify function.

TokenType

A single character string representing the 'type' of a token discovered while parsing a raw SQL string. One of:

• (
• )
• [
• ]
• ,
• ;
• .
• ..
• :
• ::
• k (keyword)
• i (identifier)
• o (operator)
• ' (string constant)
• 0 (numeric constant)
• " (quoted identifier)
• $ (positional parameter)
• b (binary bit-string)
• x (hex bit-string)
• c (comment)

Token

A Tuple comprised of a TokenType and an optional string holding the 'value' of the token. From the above list, token types k, i, o, ', 0, ", $, b, x, and c will have a value.

PgSqlMinifyOptions

An interface defining options that may be passed to the minify or lex functions. It contains the following (optional) members:

• keywords - a Set of string values defining the subset of identifiers that are considered keywords. The main difference between a keyword and an identifier is that the minify function will insert a space between a keyword and a ( token, but will not insert a space between and identifier and a ( token.
• includeComments - a boolean value that defaults to false that controls whether the minify function includes comment tokens or skips them. Because the minify function attempts to generate SQL without newline characters, any 'to end of line' comments are converted to C-style comments, newlines and tabs are converted to a single space, and consecutive whitespace characters are ignored.
• includeTrailingSemicolon - a boolean value that defaults to true that controls whether to include any trailing semicolon in the minified string. If true, any statement that (for whatever reason) only includes a semicolon is left alone.

lex

A function that analyzes a raw (valid) SQL string and returns an array of Token tuples. For example:

import { lex } from 'pgsql-minify';
:
const rawSQL = 'select    abc  from       def   ;   ';
const tokens = lex(rawSQL); // [[ 'k', 'select' ], [ 'i', 'abc' ], [ 'k', 'from' ], [ 'i', 'def' ], [ ';' ]]
:

The function takes an instance of PgSqlMinifyOptions as an optional second parameter to allow the default set of keywords to be overridden.

minify

A function that converts a raw (valid) SQL string into a standardised, 'minified' format with minimal whitespace. Here are some examples of actual output from the minify function:

(before)

select  col1,  col2,col3,
        col4, ( col5+(col6*col7)  )
from    sometable as t1
    join  othertable as t2
        on  t2.st_id = t1.id
;

(after)

select col1, col2, col3, col4, (col5 + (col6 * col7)) from sometable as t1 join othertable as t2 on t2.st_id = t1.id;

(before)

select ts -- This is the row creation timestamp
from   blah
Order
BY     1
;

(after - excluding comments)

select ts from blah order by 1;

(after - including comments)

select ts /* This is the row creation timestamp */ from blah order by 1;

Maintainer

• Steve Baldwin ([email protected])