feat: add support for import assertions (#74)

* feat: add support for import assertions

* dynamic import adjustments

* byte optimization

* fixup readme substring

Makefile

@@ -5,7 +5,7 @@ lib/lexer.wasm: src/lexer.h src/lexer.c
 	@mkdir -p lib
 	../wasi-sdk-11.0/bin/clang src/lexer.c --sysroot=../wasi-sdk-11.0/share/wasi-sysroot -o lib/lexer.wasm -nostartfiles \
 	-Wl,-z,stack-size=13312,--no-entry,--compress-relocations,--strip-all,\
-	--export=parse,--export=sa,--export=e,--export=ri,--export=re,--export=is,--export=ie,--export=ss,--export=ip,--export=se,--export=id,--export=es,--export=ee,--export=f,--export=__heap_base \
+	--export=parse,--export=sa,--export=e,--export=ri,--export=re,--export=is,--export=ie,--export=ss,--export=ip,--export=se,--export=ai,--export=as,--export=ae,--export=id,--export=es,--export=ee,--export=f,--export=__heap_base \
 	-Wno-logical-op-parentheses -Wno-parentheses \
 	-Oz
 

README.md

@@ -43,47 +43,60 @@ import { init, parse } from 'es-module-lexer/dist/lexer.js';
   await init;
 
   const source = `
-    import { a } from 'asdf';
+    import { name } from 'mod';
+    import json from './json.json' assert { type: 'json' }
     export var p = 5;
     export function q () {
 
     };
 
     // Comments provided to demonstrate edge cases
-    import /*comment!*/ ('asdf');
+    import /*comment!*/ ('asdf', { assert: { type: 'json' }});
     import /*comment!*/.meta.asdf;
   `;
 
   const [imports, exports] = parse(source, 'optional-sourcename');
 
-  // Returns "asdf"
+  // Returns "mod"
   imports[0].n
   source.substring(imports[0].s, imports[0].e);
-  // "s" is shorthand for "start"
-  // "e" is shorthand for "end"
+  // "s" = start
+  // "e" = end
 
-  // Returns "import { a } from 'asdf';"
+  // Returns "import { name } from 'mod';"
   source.substring(imports[0].ss, imports[0].se);
-  // "ss" is shorthand for "statement start"
-  // "se" is shorthand for "statement end"
+  // "ss" = statement start
+  // "se" = statement end
+
+  // Returns "assert"
+  source.slice(imports[1].a, 6);
+  // "a" = assert
+
+  // Returns "{ type: 'json' }"
+  source.substring(imports[1].as, imports[1].ae);
+  // "as" = assert start
+  // "ae" = assert end
 
   // Returns "p,q"
   exports.toString();
 
-  // Dynamic imports are indicated by imports[1].d > -1
+  // Dynamic imports are indicated by imports[2].d > -1
   // In this case the "d" index is the start of the dynamic import
   // Returns true
-  imports[1].d > -1;
+  imports[2].d > -1;
 
   // Returns "asdf"
-  imports[1].n
-  source.substring(imports[1].s, imports[1].e);
+  imports[2].n
+  // Returns "'asdf'"
+  source.substring(imports[2].s, imports[2].e);
   // Returns "import /*comment!*/ ("
-  source.substring(imports[1].d, imports[1].s);
-  // Returns "import /*comment!*/ ('asdf')"
-  source.substring(imports[1].d, imports[1].e + 1);
-  // imports[1].ss and imports[1].se is not meaningful 
-  // because dynamic import is not a statement
+  source.substring(imports[2].d, imports[2].s);
+  // Returns "import /*comment!*/ ('asdf', { assert: { type: 'json' } })"
+  source.substring(imports[2].d, imports[2].se + 1);
+  // Returns "{ assert: { type: 'json' } }"
+  source.substring(imports[2].a, imports[2].e);
+  // ss is the same as d
+  // as, ae not used for dynamic imports
 
   // import.meta is indicated by imports[2].d === -2
   // Returns true
@@ -193,3 +206,4 @@ MIT
 
 [travis-url]: https://travis-ci.org/guybedford/es-module-lexer
 [travis-image]: https://travis-ci.org/guybedford/es-module-lexer.svg?branch=master
+