output mithril, stream and ospec esm versions on build - fixes #2112 (#2194)

* output mithril, stream and ospec esm versions on build

* Add esm bundles

* [request] Clearer error message for JSON deserialization failure (#2195)

* Bundled output for commit fd7cf8041e [skip ci]

* Fix #1714 conditionally halting stream (#2200)

* Fix #1714 conditionally halting stream

* Add note in changelog

* Do not include stream as named export in mithril.esm.js

* Rename mithril.min.esm.js to mithril.esm.min.js

* Add esm files to eslintignore

* Add named exports

* Add hyperscript `m` as named export

* Add builds with export changes

* checkout regular bundled files

* Change .esm.js to .mjs

* Update pkg module to point to .mjs

* Fix for export names to avoid collision

* Updated bundled files

esm.js

@@ -0,0 +1,68 @@
+"use strict"
+
+/*
+
+This script will create esm compatible scripts
+from the already compiled versions of:
+
+- mithril.js > mithril.mjs
+- mithril.min.js > mithril.min.mjs
+- /stream/stream.js > stream.mjs
+
+*/
+
+var fs = require("fs")
+
+var namedExports = [
+	"m",
+	"trust",
+	"fragment",
+	"mount",
+	"route",
+	"withAttr",
+	"render",
+	"redraw",
+	"request",
+	"jsonp",
+	"parseQueryString",
+	"buildQueryString",
+	"version",
+	"vnode",
+	"PromisePolyfill"
+]
+
+var mithril = fs.readFileSync("mithril.js", "utf8")
+fs.writeFileSync("mithril.mjs",
+	mithril.slice(
+		mithril.indexOf("\"use strict\"") + 13,
+		mithril.lastIndexOf("if (typeof module")
+	)
+	+ "\nexport default m"
+	// The exports are declared with prefixed underscores to avoid overwriting previously
+	// declared variables with the same name
+	+ "\nvar " + namedExports.map(function(n) { return "_" + n + " = m." + n }).join(",")
+	+ "\nexport {" + namedExports.map(function(n) { return "_" + n + " as " + n }).join(",") + "}"
+)
+
+var mithrilMin = fs.readFileSync("mithril.min.js", "utf8")
+var mName = mithrilMin.match(/window\.m=([a-z])}/)[1]
+fs.writeFileSync("mithril.min.mjs",
+	mithrilMin.slice(
+		12,
+		mithrilMin.lastIndexOf("\"undefined\"!==typeof module")
+	)
+	+ "export default " + mName + ";"
+	// The exports are declared with prefixed underscores to avoid overwriting previously
+	// declared variables with the same name
+	+ "var " + namedExports.map(function(n) { return "_" + n + "=m." + n }).join(",") + ";"
+	+ "export {" + namedExports.map(function(n) { return "_" + n + " as " + n }).join(",") + "};"
+)
+
+var stream = fs.readFileSync("stream/stream.js", "utf8")
+fs.writeFileSync("stream/stream.mjs",
+	stream.slice(
+		stream.indexOf("\"use strict\"") + 13,
+		stream.lastIndexOf("if (typeof module")
+	)
+	+ "\nexport default createStream"
+)