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+/*
+  2022-08-16
+
+  The author disclaims copyright to this source code.  In place of a
+  legal notice, here is a blessing:
+
+  *   May you do good and not evil.
+  *   May you find forgiveness for yourself and forgive others.
+  *   May you share freely, never taking more than you give.
+
+  ***********************************************************************
+
+  A basic demonstration of the SQLite3 OO API #1, shorn of assertions
+  and the like to improve readability.
+*/
+'use strict';
+(function(){
+  const toss = function(...args){throw new Error(args.join(' '))};
+  const debug = console.debug.bind(console),
+        log = console.log.bind(console),
+        warn = console.warn.bind(console),
+        error = console.error.bind(console);
+
+  const demo1 = function(sqlite3){
+    const capi = sqlite3.capi,
+          oo = sqlite3.oo1,
+          wasm = capi.wasm;
+
+    const dbName = (
+      0 ? "" : capi.sqlite3_web_persistent_dir()
+    )+"/mydb.sqlite3"
+    if(0 && capi.sqlite3_web_persistent_dir()){
+      capi.wasm.sqlite3_wasm_vfs_unlink(dbName);
+    }
+    const db = new oo.DB(dbName);
+    log("db =",db.filename);
+    /**
+       Never(!) rely on garbage collection to clean up DBs and
+       (especially) statements. Always wrap their lifetimes in
+       try/finally construct...
+    */
+    try {
+      log("Create a table...");
+      db.exec("CREATE TABLE IF NOT EXISTS t(a,b)");
+      //Equivalent:
+      db.exec({
+        sql:"CREATE TABLE IF NOT EXISTS t(a,b)"
+        // ... numerous other options ... 
+      });
+      // SQL can be either a string or a byte array
+
+      log("Insert some data using exec()...");
+      let i;
+      for( i = 1; i <= 5; ++i ){
+        db.exec({
+          sql: "insert into t(a,b) values (?,?)",
+          // bind by parameter index...
+          bind: [i, i*2]
+        });
+        db.exec({
+          sql: "insert into t(a,b) values ($a,$b)",
+          // bind by parameter name...
+          bind: {$a: i * 3, $b: i * 4}
+        });
+      }    
+
+      log("Insert using a prepared statement...");
+      let q = db.prepare("insert into t(a,b) values(?,?)");
+      try {
+        for( i = 100; i < 103; ++i ){
+          q.bind( [i, i*2] ).step();
+          q.reset();
+        }
+        // Equivalent...
+        for( i = 103; i <= 105; ++i ){
+          q.bind(1, i).bind(2, i*2).stepReset();
+        }
+      }finally{
+        q.finalize();
+      }
+
+      log("Query data with exec() using rowMode 'array'...");
+      db.exec({
+        sql: "select a from t order by a limit 3",
+        rowMode: 'array', // 'array', 'object', or 'stmt' (default)
+        callback: function(row){
+          log("row ",++this.counter,"=",row);
+        }.bind({counter: 0})
+      });
+
+      log("Query data with exec() using rowMode 'object'...");
+      db.exec({
+        sql: "select a as aa, b as bb from t order by aa limit 3",
+        rowMode: 'object',
+        callback: function(row){
+          log("row ",++this.counter,"=",row);
+        }.bind({counter: 0})
+      });
+
+      log("Query data with exec() using rowMode 'stmt'...");
+      db.exec({
+        sql: "select a from t order by a limit 3",
+        rowMode: 'stmt', // stmt === the default
+        callback: function(row){
+          log("row ",++this.counter,"get(0) =",row.get(0));
+        }.bind({counter: 0})
+      });
+
+      log("Query data with exec() using rowMode INTEGER (result column index)...");
+      db.exec({
+        sql: "select a, b from t order by a limit 3",
+        rowMode: 1, // === result column 1
+        callback: function(row){
+          log("row ",++this.counter,"b =",row);
+        }.bind({counter: 0})
+      });
+
+      log("Query data with exec() without a callback...");
+      let resultRows = [];
+      db.exec({
+        sql: "select a, b from t order by a limit 3",
+        rowMode: 'object',
+        resultRows: resultRows
+      });
+      log("Result rows:",resultRows);
+
+      log("Create a scalar UDF...");
+      db.createFunction({
+        name: 'twice',
+        callback: function(arg){ // note the call arg count
+          return arg + arg;
+        }
+      });
+      log("Run scalar UDF and collect result column names...");
+      let columnNames = [];
+      db.exec({
+        sql: "select a, twice(a), twice(''||a) from t order by a desc limit 3",
+        columnNames: columnNames,
+        rowMode: 'stmt',
+        callback: function(row){
+          log("a =",row.get(0), "twice(a) =", row.get(1),
+              "twice(''||a) =",row.get(2));
+        }
+      });
+      log("Result column names:",columnNames);
+
+      if(0){
+        warn("UDF will throw because of incorrect arg count...");
+        db.exec("select twice(1,2,3)");
+      }
+
+      try {
+        db.transaction( function(D) {
+          D.exec("delete from t");
+          log("In transaction: count(*) from t =",db.selectValue("select count(*) from t"));
+          throw new sqlite3.SQLite3Error("Demonstrating transaction() rollback");
+        });
+      }catch(e){
+        if(e instanceof sqlite3.SQLite3Error){
+          log("Got expected exception from db.transaction():",e.message);
+          log("count(*) from t =",db.selectValue("select count(*) from t"));
+        }else{
+          throw e;
+        }
+      }
+
+      try {
+        db.savepoint( function(D) {
+          D.exec("delete from t");
+          log("In savepoint: count(*) from t =",db.selectValue("select count(*) from t"));
+          D.savepoint(function(DD){
+            const rows = [];
+            D.exec({
+              sql: ["insert into t(a,b) values(99,100);",
+                    "select count(*) from t"],
+              rowMode: 0,
+              resultRows: rows
+            });
+            log("In nested savepoint. Row count =",rows[0]);
+            throw new sqlite3.SQLite3Error("Demonstrating nested savepoint() rollback");
+          })
+        });
+      }catch(e){
+        if(e instanceof sqlite3.SQLite3Error){
+          log("Got expected exception from nested db.savepoint():",e.message);
+          log("count(*) from t =",db.selectValue("select count(*) from t"));
+        }else{
+          throw e;
+        }
+      }
+
+    }finally{
+      db.close();
+    }
+
+    /**
+       Misc. DB features:
+
+       - get change count (total or statement-local, 32- or 64-bit)
+       - get its file name
+       - selectValue() takes SQL and returns first column of first row.
+    
+       Misc. Stmt features:
+
+       - Various forms of bind() 
+       - clearBindings()
+       - reset()
+       - Various forms of step()
+       - Variants of get() for explicit type treatment/conversion,
+         e.g. getInt(), getFloat(), getBlob(), getJSON()
+       - getColumnName(ndx), getColumnNames()
+       - getParamIndex(name)
+    */
+  }/*demo1()*/;
+
+  const runDemos = function(Module){
+    //log("Module.sqlite3",Module);
+    const sqlite3 = Module.sqlite3,
+          capi = sqlite3.capi;
+    log("Loaded module:",capi.sqlite3_libversion(), capi.sqlite3_sourceid());
+    log("sqlite3 namespace:",sqlite3);
+    try {
+      demo1(sqlite3);
+    }catch(e){
+      error("Exception:",e.message);
+      throw e;
+    }
+  };
+
+  //self.sqlite3TestModule.sqlite3ApiConfig.persistentDirName = "/hi";
+  self.sqlite3TestModule.initSqlite3().then(runDemos);
+})();