107 lines
3.2 KiB
JavaScript
107 lines
3.2 KiB
JavaScript
#!/usr/bin/env node
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var fs = require("fs"),
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path = require("path"),
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commander = require("commander"),
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topojson = require("../");
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commander
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.version(require("../package.json").version)
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.usage("[options] <name=file>…")
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.description("Converts TopoJSON objects to GeoJSON features.")
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.option("-i, --in <file>", "input topology file name; defaults to “-” for stdin", "-")
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.option("-l, --list", "list the object names on the input topology")
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.option("-n, --newline-delimited", "output newline-delimited JSON")
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.parse(process.argv);
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if (!commander.list === commander.args.length < 1) {
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console.error();
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console.error(" error: " + (commander.list ? "--list does not take arguments" : "no arguments specified"));
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console.error();
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process.exit(1);
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}
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read(commander.in).then(write).catch(abort);
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function read(file) {
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return new Promise(function(resolve, reject) {
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var data = [];
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readStream(file)
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.on("data", function(d) { data.push(d); })
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.on("end", function() { resolve(JSON.parse(Buffer.concat(data))); })
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.on("error", reject);
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});
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}
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function readStream(file) {
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return file === "-" ? process.stdin : fs.createReadStream(file);
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}
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function write(topology) {
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var write, writer = commander.newlineDelimited ? writeNewlineDelimitedFeature : writeFeature, name;
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if (commander.list) {
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for (name in topology.objects) {
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console.log(name);
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}
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return;
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}
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write = Promise.resolve();
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commander.args.forEach(function(specifier) {
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var i = specifier.indexOf("="),
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file = i >= 0 ? specifier.slice(i + 1) : specifier,
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name = i >= 0 ? specifier.slice(0, i) : path.basename(specifier, path.extname(specifier));
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if (!(name in topology.objects)) {
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console.error();
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console.error(" error: object “" + name + "” not found");
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console.error();
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process.exit(1);
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}
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write = write.then(writer(file, topojson.feature(topology, topology.objects[name])));
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});
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return write;
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}
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function writeStream(file) {
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return (file === "-" ? process.stdout : fs.createWriteStream(file)).on("error", handleEpipe);
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}
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function writeFeature(file, feature) {
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return new Promise(function(resolve, reject) {
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writeStream(file).on("error", reject)[file === "-" ? "write" : "end"](JSON.stringify(feature) + "\n", function(error) {
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if (error) reject(error);
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else resolve();
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});
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});
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}
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function writeNewlineDelimitedFeature(file, feature) {
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return feature == null || feature.type != "FeatureCollection" ? writeFeature(file, feature) : new Promise(function(resolve, reject) {
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var stream = writeStream(file).on("error", reject), i = -1, n = feature.features.length;
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(function writeNext(error) {
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if (error) return void reject(error);
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if (++i >= n) {
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if (file !== "-") stream.end(writeEnd);
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else writeEnd();
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} else {
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stream.write(JSON.stringify(feature.features[i]) + "\n", writeNext);
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}
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})(null);
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function writeEnd(error) {
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if (error) return void reject(error);
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resolve();
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}
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});
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}
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function handleEpipe(error) {
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if (error.code === "EPIPE" || error.errno === "EPIPE") {
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process.exit(0);
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}
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}
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function abort(error) {
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console.error(error.stack);
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}
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