Delete implemented

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "sineql",
-  "version": "0.4.0",
+  "version": "0.5.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "sineql",
-      "version": "0.4.0",
+      "version": "0.5.0",
       "license": "ISC",
       "devDependencies": {
         "jest": "^27.5.1"

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sineql",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "description": "A simple to use graphQL clone",
   "main": "source/index.js",
   "scripts": {

source/index.js

@@ -55,9 +55,19 @@ const sineQL = (schema, { queryHandlers, createHandlers }, options = {}) => {
 					return [200, result];
 
 				case 'delete':
-					return [501, 'Keyword not yet implemented: ' + tokens[0]];
-					//TODO: implement these keywords
-					break;
+					if (!deleteHandlers) {
+						return [501, 'Delete handlers not implemented'];
+					}
+
+					if (!deleteHandlers[tokens[1]]) {
+						throw `Delete handler not implemented for that type: ${tokens[1]}`;
+					}
+
+					const deleteTree = parseDeleteTree(tokens, typeGraph, options);
+
+					const result = await deleteHandlers[tokens[1]](deleteTree, typeGraph);
+
+					return [200, result];
 
 				//no leading keyword - regular query
 				default: {
@@ -65,12 +75,12 @@ const sineQL = (schema, { queryHandlers, createHandlers }, options = {}) => {
 						return [501, 'Query handlers not implemented'];
 					}
 
-					const queryTree = parseQueryTree(tokens, typeGraph, options);
-
-					if (!queryHandlers[queryTree.typeName]) {
-						throw `Query handler not implemented for that type: ${queryTree.typeName}`;
+					if (!queryHandlers[tokens[0]]) {
+						throw `Query handler not implemented for that type: ${tokens[0]}`;
 					}
 
+					const queryTree = parseQueryTree(tokens, typeGraph, options);
+
 					const result = await queryHandlers[queryTree.typeName](queryTree, typeGraph);
 
 					if (options.debug) {

source/parse-delete-tree.js

@@ -0,0 +1,161 @@
+//build the tokens into a single object of types representing the initial query
+const parseDeleteTree = (tokens, typeGraph, options = {}) => {
+	let current = 1; //primed
+
+	//check this is a update command
+	if (tokens[current - 1] != 'delete') {
+		throw 'Expected delete keyword at the beginning of delete command';
+	}
+
+	current++;
+
+	//get a token that matches a type
+	if (!typeGraph[tokens[current - 1]]) {
+		throw `Expected a type in the type graph (found ${tokens[current - 1]})`;
+	}
+
+	//check that there are the correct number of '{' and '}'
+	if (tokens.reduce((running, tok) => tok == '{' ? running + 1 : tok == '}' ? running - 1 : running, 0) != 0) {
+		throw `Unequal number of '{' and '}' found`;
+	}
+
+	//check that there are the correct number of '[' and ']'
+	if (tokens.reduce((running, tok) => tok == '[' ? running + 1 : tok == ']' ? running - 1 : running, 0) != 0) {
+		throw `Unequal number of '[' and ']' found`;
+	}
+
+	//the return
+	const result = [];
+	const type = tokens[current - 1];
+
+	if (tokens[current] == '[') {
+		current++;
+	}
+
+	do {
+		//read the block of lines
+		const [block, pos] = readBlock(tokens, current, type, typeGraph, options);
+
+		//insert the typename into the top-level block
+		block['typeName'] = type;
+
+		//insert update into the top-level block
+		block['delete'] = true;
+
+		current = pos;
+
+		result.push(block);
+	} while (tokens[current] && tokens[current] != ']');
+
+	//finally
+	return result;
+};
+
+const readBlock = (tokens, current, superType, typeGraph, options) => {
+	//scan the '{'
+	if (tokens[current++] != '{') {
+		throw `Expected '{' at beginning of a block (found ${tokens[current - 1]})`;
+	}
+
+	//result
+	const result = {};
+
+	//scan each "line" in this block
+	while(tokens[current++] && tokens[current - 1] != '}') {
+		//check for block-level keywords (modifiers need to form a chain from the leaf)
+		let modifier = null;
+		if (['match'].includes(tokens[current - 1])) {
+			modifier = tokens[current - 1];
+			current++;
+		}
+
+		//read field name
+		const fieldName = tokens[current - 1];
+
+		if (options.debug) {
+			console.log(`Trying to process field ${fieldName}`);
+		}
+
+		//if the field is not present in the type
+		if (!typeGraph[superType][fieldName]) {
+			throw `Unexpected field name ${fieldName} in type ${superType}`;
+		}
+
+		//if the field is non-scalar, read the sub-block
+		if (!typeGraph[typeGraph[superType][fieldName].typeName].scalar) {
+			if (tokens[current] == '[') {
+				current++;
+			}
+
+			do {
+				//recurse
+				const [block, pos] = readBlock(tokens, current, typeGraph[superType][fieldName].typeName, typeGraph, options);
+
+				//insert the typename into the block
+				block['typeName'] = typeGraph[superType][fieldName].typeName;
+
+				//insert the unique modifier if it's set
+				block['unique'] = typeGraph[superType][fieldName].unique;
+
+				//insert the block-level modifier signal
+				if (modifier) {
+					block[modifier] = true;
+				} else {
+					throw `Modifier expected for ${fieldName} (match)`;
+				}
+
+				//insert into result
+				result[fieldName] = result[fieldName] || [];
+				result[fieldName].push(block);
+
+				current = pos; //pos points past the end of the block
+
+				if (options.debug) {
+					console.log(`${fieldName}:`);
+					console.dir(result[fieldName], { depth: null });
+				}
+			} while (tokens[current] && tokens[current] == '{');
+			current++;
+
+			continue;
+		}
+
+		//scalar
+		else {
+			//save the typeGraph type into result
+			result[fieldName] = JSON.parse(JSON.stringify( typeGraph[ typeGraph[superType][fieldName].typeName ] ));
+
+			//insert the unique modifier if it's set
+			result[fieldName]['unique'] = typeGraph[superType][fieldName].unique;
+
+			//insert the block-level modifier signal
+			if (modifier) {
+				//handle integers and floats exposed to the user
+				switch(result[fieldName].typeName) {
+					case 'Integer': 
+					result[fieldName][modifier] = parseInt(tokens[current++]);
+						break;
+
+					case 'Float':
+						result[fieldName][modifier] = parseFloat(tokens[current++]);
+						break;
+
+					default: //everything else is a string (including booleans)
+						result[fieldName][modifier] = tokens[current++];
+				}
+			} else {
+				throw `Modifier expected for ${fieldName} (match)`;
+			}
+
+			if (options.debug) {
+				console.log(`${fieldName}: `, result[fieldName]);
+			}
+
+			continue;
+		}
+	}
+
+	return [result, current];
+};
+
+module.exports = parseDeleteTree;

test/parse-delete-tree.test.js

@@ -0,0 +1,111 @@
+const buildTypeGraph = require('../source/build-type-graph');
+const parseInput = require('../source/parse-input');
+const parseDeleteTree = require('../source/parse-delete-tree');
+
+//schemas
+const simpleSchema = `
+
+scalar Date
+
+type Book {
+	unique String title
+	Date published
+	Float rating
+}
+
+type Author {
+	unique String name
+	Book books
+}
+
+`;
+
+const simpleBookQuery = `
+
+delete Book {
+	match title "The Wind in the Willows"
+}
+
+`;
+
+const compoundBookQuery = `
+
+delete Book [
+	{
+		match title "The Philosopher's Kidney Stone"
+	}
+	{
+		match title "The Chamber Pot of Secrets"
+	}
+	{
+		match title "The Prisoner of Aunt Kazban"
+	}
+	{
+		match title "The Goblet of the Fire Cocktail"
+	}
+	{
+		match title "The Order for Kleenex"
+	}
+	{
+		match title "The Half-Priced Pharmacy"
+	}
+	{
+		match title "Yeah, I Got Nothing"
+	}
+]
+
+`;
+
+const multipleFieldsQuery = `
+
+delete Book {
+	match title "The Wind in the Willows"
+	match published "1908-04-01"
+}
+
+`;
+
+//do stuff
+test('parseDeleteTree - delete a single book', () => {
+	//setup
+	const tokens = parseInput(simpleBookQuery, true);
+	const graph = buildTypeGraph(simpleSchema);
+
+	//process
+	const deleteTree = parseDeleteTree(tokens, graph);
+
+	//inspect
+	expect(deleteTree.length).toEqual(1);
+	expect(deleteTree[0].delete).toEqual(true);
+	expect(deleteTree[0].title.match).toEqual('The Wind in the Willows');
+});
+
+test('parseDeleteTree - delete multiple books', () => {
+	//setup
+	const tokens = parseInput(compoundBookQuery, true);
+	const graph = buildTypeGraph(simpleSchema);
+
+	//process
+	const deleteTree = parseDeleteTree(tokens, graph);
+
+	//inspect
+	expect(deleteTree.length).toEqual(7);
+	expect(deleteTree[0].delete).toEqual(true);
+	expect(deleteTree[0].title.match).toEqual('The Philosopher\'s Kidney Stone');
+});
+
+test('parseDeleteTree - delete a book based on multiple match conditions', () => {
+	//setup
+	const tokens = parseInput(multipleFieldsQuery, true);
+	const graph = buildTypeGraph(simpleSchema);
+
+	//process
+	const deleteTree = parseDeleteTree(tokens, graph);
+
+	//inspect
+	expect(deleteTree.length).toEqual(1);
+	expect(deleteTree[0].delete).toEqual(true);
+	expect(deleteTree[0].title.match).toEqual('The Wind in the Willows');
+	expect(deleteTree[0].published.match).toEqual('1908-04-01');
+});
+