v0.6.57

CHANGELOG.md

@@ -1,3 +1,6 @@
+v0.6.57
+* Added io.ifile() method for creating dynamic input files in the run command
+
 v0.6.56
 * Added support for importing ES modules using the -require command.
 * Removed the -require init= function.

REFERENCE.md

@@ -1,6 +1,6 @@
 # COMMAND REFERENCE
 
-This documentation applies to version 0.6.56 of mapshaper's command line program. Run `mapshaper -v` to check your version. For an introduction to the command line tool, read [this page](https://github.com/mbloch/mapshaper/wiki/Introduction-to-the-Command-Line-Tool) first.
+This documentation applies to version 0.6.57 of mapshaper's command line program. Run `mapshaper -v` to check your version. For an introduction to the command line tool, read [this page](https://github.com/mbloch/mapshaper/wiki/Introduction-to-the-Command-Line-Tool) first.
 
 ## Command line syntax
 
@@ -1072,7 +1072,7 @@ Common options: `target=`
 
 Expression context:
 
-`target` object
+`target` object provides data and information about the command's target layer
 - `target.layer_name`  Name of layer
 - `target.geojson`  (getter) Returns a GeoJSON FeatureCollection for the layer
 - `target.geometry_type` One of: polygon, polyline, point, `undefined`
@@ -1082,11 +1082,10 @@ Expression context:
 - `target.bbox` GeoJSON-style bounding box
 - `target.proj4` PROJ-formatted string giving the CRS (coordinate reference system) of the layer
 
-`io` object (useful for importing dynamically generated datasets; see example below)
-- `io.addInputFile(<filename>, <data>)` Add JSON data that can be referenced by filename in the command string generated by `-run`.
+`io` object has a method for passing data to the `-i` command.
+- `io.ifile(<filename>, <data>)` Create a temp file to use as input in a `-run` command (see example 2 below)
 
-
-**Example 1:** Apply a custom projection based on the layer extent
+**Example 1:** Apply a custom projection based on the layer extent.
 
 ```bash
 $ mapshaper -i country.shp -require projection.js -run '-proj {tmerc(target.bbox)}' -o
@@ -1101,19 +1100,22 @@ module.exports.tmerc = function(bbox) {
 };
 ```
 
-**Example 2:** Convert points to a Voronoi diagram
+**Example 2:** Convert points to a Voronoi diagram using a template expression
+together with an external script.
 
 ```bash
-$ mapshaper -i points.geojson -require script.js -run '-i {voronoi(target, io)}' -o
+$ mapshaper points.geojson \
+  -require script.js \
+  -run '-i {io.ifile("voronoi.json", voronoi(target.geojson, target.bbox))}' \
+  -o
 ```
 
 ```javascript
 // contents of script.js file
-module.exports.voronoi = async function(target, io) {
+module.exports.voronoi = async function(points, bbox) {
   const d3 = await import('d3-delaunay'); // installed locally
-  const points = target.geojson; // assume 'Point' geometry
-  const coords = input.features.map(feat => feat.geometry.coordinates);
-  const voronoi = d3.Delaunay.from(coords).voronoi(target.bbox); // constrain to data bounds
+  const coords = points.features.map(feat => feat.geometry.coordinates);
+  const voronoi = d3.Delaunay.from(coords).voronoi(bbox);
   const features = Array.from(voronoi.cellPolygons()).map(function(ring, i) {
     return {
       type: 'Feature',
@@ -1124,8 +1126,7 @@ module.exports.voronoi = async function(target, io) {
       }
     };
   });
-  io.addInputFile('polygons.json', {type: 'FeatureCollection', features: features})
-  return 'polygons.json';
+  return {type: 'FeatureCollection', features: features};
 };
 ```
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mapshaper",
-  "version": "0.6.56",
+  "version": "0.6.57",
   "description": "A tool for editing vector datasets for mapping and GIS.",
   "keywords": [
     "shapefile",

src/commands/mapshaper-run.mjs

@@ -4,7 +4,7 @@ import { parseCommands } from '../cli/mapshaper-parse-commands';
 import { stop, message, truncateString } from '../utils/mapshaper-logging';
 import utils from '../utils/mapshaper-utils';
 import cmd from '../mapshaper-cmd';
-import { getIOProxy } from '../expressions/mapshaper-job-proxy';
+import { getIOProxy } from '../expressions/mapshaper-io-proxy';
 import { evalTemplateExpression } from '../expressions/mapshaper-template-expressions';
 import { commandTakesFileInput } from '../cli/mapshaper-command-info';
 

src/expressions/mapshaper-io-proxy.mjs

@@ -0,0 +1,17 @@
+import utils from '../utils/mapshaper-utils';
+
+export function getIOProxy(job) {
+  async function addInputFile(filename, content) {
+    if (utils.isPromise(content)) {
+      content = await content;
+    }
+    io._cache[filename] = content;
+    return filename; // return filename to support -run '-i {io.ifile()}'
+  }
+  var io = {
+    _cache: {},
+    addInputFile,
+    ifile: addInputFile // ifile() is an alias for addInputFile
+  };
+  return io;
+}

test/run-test.mjs

@@ -57,6 +57,18 @@ describe('mapshaper-run.js', function () {
       assert.deepEqual(JSON.parse(out['selection.json']), [{foo: 'bam'}])
     })
 
+   it('supports io.ifile() alias', async function() {
+      var data = [{foo: 'bar'}, {foo: 'baz'}, {foo: 'bam'}];
+      var include = '{ \
+        subset: async function(fc) { \
+          return [fc.features[2].properties]; \
+        }}';
+      var cmd = `-i data.json -include include.js
+        -run '{io.ifile("selection.json", subset(target.geojson))}' -o`;
+      var out = await api.applyCommands(cmd, {'include.js': include, 'data.json': data});
+      assert.deepEqual(JSON.parse(out['selection.json']), [{foo: 'bam'}])
+    })
+
     it('supports creating a command on-the-fly and running it', function (done) {
       var data = [{foo: 'bar'}];
       var include = '{ \