knex-postgis

postgis extension for knex

Usage no npm install needed!

<script type="module">
  import knexPostgis from 'https://cdn.skypack.dev/knex-postgis';
</script>

README

knex-postgis

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Extension for use postgis functions in knex SQL query builder.

Example

This example show the sql generated by the extension.

const knex = require('knex');
const knexPostgis = require('knex-postgis');

const db = knex({
  client: 'postgres'
});

// install postgis functions in knex.postgis;
const st = knexPostgis(db);
/* or:
 * knexPostgis(db);
 * const st = db.postgis;
 */

// insert a point
const sql1 = db.insert({
  id: 1,
  geom: st.geomFromText('Point(0 0)', 4326)
}).into('points').toString();
console.log(sql1);
// insert into "points" ("geom", "id") values (ST_geomFromText('Point(0 0)'), '1')

// find all points return point in wkt format
const sql2 = db.select('id', st.asText('geom')).from('points').toString();
console.log(sql2);
// select "id", ST_asText("geom") as "geom" from "points"

// all methods support alias
const sql3 = db.select('id', st.asText(st.centroid('geom')).as('centroid')).from('geometries').toString();
console.log(sql3);
// select "id", ST_asText(ST_centroid("geom")) as "centroid" from "geometries"

Currently supported functions

Define extra functions

const knex = require('knex');
const knexPostgis = require('knex-postgis');

const db = knex({
  client: 'postgres'
});

knexPostgis(db);

db.postgisDefineExtras((knex, formatter) => ({
  utmzone(geom) {
    return knex.raw('utmzone(?)', [formatter.wrapWKT(geom)]);
  }
}));
//now you can use st.utmzone function in the same way as predefined functions