Properly handle unsafe numbers - fixes porsager#27

porsager · porsager · commit 8154e1ebff5b · 2020-02-03T17:24:56.000+01:00
diff --git a/README.md b/README.md
@@ -408,6 +408,16 @@ prexit(async () => {
 
 ```
 
+## Numbers, bigint, numeric
+
+`Number` in javascript is only able to represent 2<sup>53</sup>-1 safely which means that types in PostgreSQLs like `bigint` and `numeric` won't fit into `Number`.
+
+Since Node.js v10.4 we can use [`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) to match the PostgreSQL type `bigint`, so Postgres.js will use BigInt if running on v10.4 or later. For older versions `bigint` will be returned as a string.
+
+There is currently no way to handle `numeric / decimal` in a native way in Javascript, so these and similar will be returned as `string`.
+
+You can of course handle types like these using [custom types](#types) if you want to.
+
 ## The Connection Pool
 
 Connections are created lazily once a query is created. This means that simply doing const `sql = postgres(...)` won't have any effect other than instantiating a new `sql` instance. 
diff --git a/lib/types.js b/lib/types.js
@@ -2,15 +2,15 @@ const char = (acc, [k, v]) => (acc[k.charCodeAt(0)] = v, acc)
 const entries = o => Object.keys(o).map(x => [x, o[x]])
 
 // These were the fastest ways to do it in Node.js v12.11.1 (add tests to revise if this changes)
-const types = module.exports.types = {
+const types = module.exports.types = Object.assign({
   string: {
     to: 25,
     from: null,             // defaults to string
     serialize: x => '' + x
   },
   number: {
     to: 1700,
-    from: [20, 21, 23, 26, 700, 701, 790, 1700],
+    from: [21, 23, 26, 700],
     serialize: x => '' + x,
     parse: x => +x
   },
@@ -22,7 +22,7 @@ const types = module.exports.types = {
   },
   boolean: {
     to: 16,
-    from: [16],
+    from: 16,
     serialize: x => x === true ? 't' : 'f',
     parse: x => x === 't'
   },
@@ -34,11 +34,20 @@ const types = module.exports.types = {
   },
   bytea: {
     to: 17,
-    from: [17],
+    from: 17,
     serialize: x => '\\x' + x.toString('hex'),
     parse: x => Buffer.from(x.slice(2), 'hex')
   }
-}
+},
+  typeof BigInt === 'undefined' ? {} : {
+    bigint: {
+      to: 20,
+      from: [20],
+      parse: data => BigInt(data), // eslint-disable-line
+      serialize: bigint => bigint.toString()
+    }
+  }
+)
 
 const defaultHandlers = typeHandlers(types)
 
@@ -57,17 +66,12 @@ module.exports.mergeUserTypes = function(types) {
 
 function typeHandlers(types) {
   return Object.keys(types).reduce((acc, k) => {
-    types[k].from && types[k].from.forEach(x => acc.parsers[x] = types[k].parse)
+    types[k].from && [].concat(types[k].from).forEach(x => acc.parsers[x] = types[k].parse)
     acc.serializers[types[k].to] = types[k].serialize
     return acc
   }, { parsers: {}, serializers: {} })
 }
 
-const type = {
-  number: 1700,
-  boolean: 16
-}
-
 module.exports.escape = function escape(str) {
   let result = ''
   let q = str[0] < 10 || str[0] === '$'
@@ -89,6 +93,12 @@ module.exports.escape = function escape(str) {
   return (q ? '"' : '') + (q ? result + str.slice(last, str.length) : str) + (q ? '"' : '')
 }
 
+const type = {
+  number: 1700,
+  bigint: 20,
+  boolean: 16
+}
+
 module.exports.inferType = function inferType(x) {
   return (x && x.type) || (x instanceof Date
     ? 1184
diff --git a/tests/index.js b/tests/index.js
@@ -87,7 +87,7 @@ t('undefined to null', async() =>
 )
 
 t('Integer', async() =>
-  [1, (await sql`select ${ 1 } as x`)[0].x]
+  ['1', (await sql`select ${ 1 } as x`)[0].x]
 )
 
 t('String', async() =>
@@ -117,7 +117,7 @@ t('Empty array', async() =>
 )
 
 t('Array of Integer', async() =>
-  [3, (await sql`select ${ sql.array([1, 2, 3]) } as x`)[0].x[2]]
+  ['3', (await sql`select ${ sql.array([1, 2, 3]) } as x`)[0].x[2]]
 )
 
 t('Array of String', async() =>
@@ -130,11 +130,11 @@ t('Array of Date', async() => {
 })
 
 t('Nested array n2', async() =>
-  [4, (await sql`select ${ sql.array([[1, 2], [3, 4]]) } as x`)[0].x[1][1]]
+  ['4', (await sql`select ${ sql.array([[1, 2], [3, 4]]) } as x`)[0].x[1][1]]
 )
 
 t('Nested array n3', async() =>
-  [6, (await sql`select ${ sql.array([[[1, 2]], [[3, 4]], [[5, 6]]]) } as x`)[0].x[2][0][1]]
+  ['6', (await sql`select ${ sql.array([[[1, 2]], [[3, 4]], [[5, 6]]]) } as x`)[0].x[2][0][1]]
 )
 
 t('Escape in arrays', async() =>
@@ -202,7 +202,7 @@ t('Transaction succeeds on caught savepoint', async() => {
     await sql`insert into test values(3)`
   })
 
-  return [2, (await sql`select count(1) from test`)[0].count]
+  return [typeof BigInt === 'undefined' ? '2' : 2n, (await sql`select count(1) from test`)[0].count]
 }, () => sql`drop table test`)
 
 t('Savepoint returns Result', async() => {
@@ -251,7 +251,7 @@ t('Transaction waits', async() => {
 }, () => sql`drop table test`)
 
 t('Helpers in Transaction', async() => {
-  return [1, (await sql.begin(async sql =>
+  return ['1', (await sql.begin(async sql =>
     await sql`select ${ sql({ x: 1 }) }`
   ))[0].x]
 })
@@ -614,7 +614,7 @@ t('dynamic column name', async() => {
 })
 
 t('dynamic select as', async() => {
-  return [2, (await sql`select ${ sql({ a: 1, b: 2 }) }`)[0].b]
+  return ['2', (await sql`select ${ sql({ a: 1, b: 2 }) }`)[0].b]
 })
 
 t('dynamic select as pluck', async() => {
@@ -825,3 +825,18 @@ t('Debug works', async() => {
 
   return ['select 1', result]
 })
+
+t('bigint is returned as BigInt', async() => [
+  'bigint',
+  typeof (await sql`select 9223372036854777 as x`)[0].x
+])
+
+ot('int is returned as Number', async() => [
+  'number',
+  typeof (await sql`select 123 as x`)[0].x
+])
+
+ot('numeric is returned as string', async() => [
+  'string',
+  typeof (await sql`select 1.2 as x`)[0].x
+])
