diff --git a/src/replacements/list/$elm$core$List$append.js b/src/replacements/list/$elm$core$List$append.js
new file mode 100644
index 0000000..088a054
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$append.js
@@ -0,0 +1,12 @@
+var $elm$core$List$append = F2(function (xs, ys) {
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+  for (; xs.b; xs = xs.b) {
+    var next = _List_Cons(xs.a, _List_Nil);
+    end.b = next;
+    end = next;
+  }
+  end.b = ys;
+
+  return tmp.b;
+});
diff --git a/src/replacements/list/$elm$core$List$concat.js b/src/replacements/list/$elm$core$List$concat.js
new file mode 100644
index 0000000..e7c946e
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$concat.js
@@ -0,0 +1,18 @@
+var $elm$core$List$concat = function (lists) {
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+  if (!lists.b) {
+    return _List_Nil;
+  }
+  for (; lists.b.b; lists = lists.b) {
+    var xs = lists.a;
+    for (; xs.b; xs = xs.b) {
+      var next = _List_Cons(xs.a, _List_Nil);
+      end.b = next;
+      end = next;
+    }
+  }
+  end.b = lists.a;
+
+  return tmp.b;
+};
diff --git a/src/replacements/list/$elm$core$List$filter.js b/src/replacements/list/$elm$core$List$filter.js
new file mode 100644
index 0000000..db8085b
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$filter.js
@@ -0,0 +1,12 @@
+var $elm$core$List$filter = F2(function (f, xs) {
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+  for (; xs.b; xs = xs.b) {
+    if (f(xs.a)) {
+      var next = _List_Cons(xs.a, _List_Nil);
+      end.b = next;
+      end = next;
+    }
+  }
+  return tmp.b;
+});
diff --git a/src/replacements/list/$elm$core$List$indexedMap.js b/src/replacements/list/$elm$core$List$indexedMap.js
new file mode 100644
index 0000000..8c4dd5d
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$indexedMap.js
@@ -0,0 +1,10 @@
+var $elm$core$List$indexedMap = F2(function (f, xs) {
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+  for (var i = 0; xs.b; i++, xs = xs.b) {
+    var next = _List_Cons(A2(f, i, xs.a), _List_Nil);
+    end.b = next;
+    end = next;
+  }
+  return tmp.b;
+});
diff --git a/src/replacements/list/$elm$core$List$intersperse.js b/src/replacements/list/$elm$core$List$intersperse.js
new file mode 100644
index 0000000..b3908a6
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$intersperse.js
@@ -0,0 +1,20 @@
+var $elm$core$List$intersperse = F2(function (sep, xs) {
+  if (!xs.b) {
+    return xs;
+  }
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+
+  end.b = _List_Cons(xs.a, _List_Nil);
+  end = end.b;
+  xs = xs.b;
+
+  for (; xs.b; xs = xs.b) {
+    var valNode = _List_Cons(xs.a, _List_Nil);
+    var sepNode = _List_Cons(sep, valNode);
+    end.b = sepNode;
+    end = valNode;
+  }
+
+  return tmp.b;
+});
diff --git a/src/replacements/list/$elm$core$List$map.js b/src/replacements/list/$elm$core$List$map.js
new file mode 100644
index 0000000..76b8ff3
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$map.js
@@ -0,0 +1,10 @@
+var $elm$core$List$map = F2(function (f, xs) {
+  var tmp = _List_Cons(undefined, _List_Nil);
+  var end = tmp;
+  for (; xs.b; xs = xs.b) {
+    var next = _List_Cons(f(xs.a), _List_Nil);
+    end.b = next;
+    end = next;
+  }
+  return tmp.b;
+});
diff --git a/src/replacements/list/$elm$core$List$partition.js b/src/replacements/list/$elm$core$List$partition.js
new file mode 100644
index 0000000..dc25acf
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$partition.js
@@ -0,0 +1,17 @@
+var $elm$core$List$partition = F2(function (f, xs) {
+  var truesHead = _List_Cons(undefined, _List_Nil);
+  var falsesHead = _List_Cons(undefined, _List_Nil);
+  var truesEnd = truesHead;
+  var falsesEnd = falsesHead;
+  for (; xs.b; xs = xs.b) {
+    var next = _List_Cons(xs.a, _List_Nil);
+    if (f(xs.a)) {
+      truesEnd.b = next;
+      truesEnd = next;
+    } else {
+      falsesEnd.b = next;
+      falsesEnd = next;
+    }
+  }
+  return _Utils_Tuple2(truesHead.b, falsesHead.b);
+});
diff --git a/src/replacements/list/$elm$core$List$unzip.js b/src/replacements/list/$elm$core$List$unzip.js
new file mode 100644
index 0000000..865f952
--- /dev/null
+++ b/src/replacements/list/$elm$core$List$unzip.js
@@ -0,0 +1,18 @@
+var $elm$core$List$unzip = function (pairs) {
+  var aHead = _List_Cons(undefined, _List_Nil);
+  var bHead = _List_Cons(undefined, _List_Nil);
+  var aEnd = aHead;
+  var bEnd = bHead;
+  for (; pairs.b; pairs = pairs.b) {
+    var tuple = pairs.a;
+
+    var aNext = _List_Cons(tuple.a, _List_Nil);
+    aEnd.b = aNext;
+    aEnd = aNext;
+
+    var bNext = _List_Cons(tuple.b, _List_Nil);
+    bEnd.b = bNext;
+    bEnd = bNext;
+  }
+  return _Utils_Tuple2(aHead.b, bHead.b);
+};
diff --git a/src/replacements/string/$elm$core$String$join.js b/src/replacements/string/$elm$core$String$join.js
new file mode 100644
index 0000000..3560010
--- /dev/null
+++ b/src/replacements/string/$elm$core$String$join.js
@@ -0,0 +1,13 @@
+var $elm$core$String$join = F2(function (sep, strs) {
+  if (!strs.b) {
+    return '';
+  }
+  var acc = '' + strs.a;
+  strs = strs.b;
+
+  for (; strs.b; strs = strs.b) {
+    acc = '' + acc + sep + strs.a;
+  }
+
+  return acc;
+});
diff --git a/src/transforms/replace.ts b/src/transforms/replace.ts
index 8e7544c..3349701 100644
--- a/src/transforms/replace.ts
+++ b/src/transforms/replace.ts
@@ -1,6 +1,7 @@
 
 import ts, { isIdentifier } from 'typescript';
 import { ast, astNodes } from './utils/create';
+import { readFilesSync } from '../fs_util';
 
 export const replace = (
   replacements: { [name: string]: string }
@@ -26,3 +27,13 @@ export const replace = (
         return ts.visitNode(sourceFile, visitor);
     };
 };
+
+
+export const from_file = (path: string) => {
+  const read = readFilesSync(__dirname + path)
+  let replacements = {}
+  if (read) {
+    replacements = read
+  }
+  return replace(replacements)
+}
\ No newline at end of file
diff --git a/src/transforms/replaceListFunctions.ts b/src/transforms/replaceListFunctions.ts
deleted file mode 100644
index 9d817ec..0000000
--- a/src/transforms/replaceListFunctions.ts
+++ /dev/null
@@ -1,172 +0,0 @@
-import ts, { isIdentifier } from 'typescript';
-import { ast } from './utils/create';
-
-const $elm$core$List$map = `
-var $elm$core$List$map = F2(function (f, xs) {
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-  for (; xs.b; xs = xs.b) {
-    var next = _List_Cons(f(xs.a), _List_Nil);
-    end.b = next;
-    end = next;
-  }
-  return tmp.b;
-});
-`;
-
-const $elm$core$List$indexedMap = `
-var $elm$core$List$indexedMap = F2(function (f, xs) {
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-  for (var i = 0; xs.b; i++, xs = xs.b) {
-    var next = _List_Cons(A2(f, i, xs.a), _List_Nil);
-    end.b = next;
-    end = next;
-  }
-  return tmp.b;
-});
-`;
-
-const $elm$core$List$filter = `
-var $elm$core$List$filter = F2(function (f, xs) {
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-  for (; xs.b; xs = xs.b) {
-    if (f(xs.a)) {
-      var next = _List_Cons(xs.a, _List_Nil);
-      end.b = next;
-      end = next;
-    }
-  }
-  return tmp.b;
-});
-`;
-
-const $elm$core$List$append = `
-var $elm$core$List$append = F2(function (xs, ys) {
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-  for (; xs.b; xs = xs.b) {
-    var next = _List_Cons(xs.a, _List_Nil);
-    end.b = next;
-    end = next;
-  }
-  end.b = ys;
-
-  return tmp.b;
-});
-`;
-
-const $elm$core$List$concat = `
-var $elm$core$List$concat = function (lists) {
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-  if (!lists.b) {
-    return _List_Nil;
-  }
-  for (; lists.b.b; lists = lists.b) {
-    var xs = lists.a;
-    for (; xs.b; xs = xs.b) {
-      var next = _List_Cons(xs.a, _List_Nil);
-      end.b = next;
-      end = next;
-    }
-  }
-  end.b = lists.a;
-
-  return tmp.b;
-};
-`;
-
-const $elm$core$List$intersperse = `
-var $elm$core$List$intersperse = F2(function (sep, xs) {
-  if (!xs.b) {
-    return xs;
-  }
-  var tmp = _List_Cons(undefined, _List_Nil);
-  var end = tmp;
-
-  end.b = _List_Cons(xs.a, _List_Nil);
-  end = end.b;
-  xs = xs.b;
-
-  for (; xs.b; xs = xs.b) {
-    var valNode = _List_Cons(xs.a, _List_Nil);
-    var sepNode = _List_Cons(sep, valNode);
-    end.b = sepNode;
-    end = valNode;
-  }
-
-  return tmp.b;
-});
-`;
-
-const $elm$core$List$partition = `
-var $elm$core$List$partition = F2(function (f, xs) {
-  var truesHead = _List_Cons(undefined, _List_Nil);
-  var falsesHead = _List_Cons(undefined, _List_Nil);
-  var truesEnd = truesHead;
-  var falsesEnd = falsesHead;
-  for (; xs.b; xs = xs.b) {
-    var next = _List_Cons(xs.a, _List_Nil);
-    if (f(xs.a)) {
-      truesEnd.b = next;
-      truesEnd = next;
-    } else {
-      falsesEnd.b = next;
-      falsesEnd = next;
-    }
-  }
-  return _Utils_Tuple2(truesHead.b, falsesHead.b);
-});
-`;
-
-const $elm$core$List$unzip = `
-var $elm$core$List$unzip = function (pairs) {
-  var aHead = _List_Cons(undefined, _List_Nil);
-  var bHead = _List_Cons(undefined, _List_Nil);
-  var aEnd = aHead;
-  var bEnd = bHead;
-  for (; pairs.b; pairs = pairs.b) {
-    var tuple = pairs.a;
-
-    var aNext = _List_Cons(tuple.a, _List_Nil);
-    aEnd.b = aNext;
-    aEnd = aNext;
-
-    var bNext = _List_Cons(tuple.b, _List_Nil);
-    bEnd.b = bNext;
-    bEnd = bNext;
-  }
-  return _Utils_Tuple2(aHead.b, bHead.b);
-};
-`;
-
-
-const replacements = {
-  $elm$core$List$map,
-  $elm$core$List$indexedMap,
-  $elm$core$List$filter,
-  $elm$core$List$append,
-  $elm$core$List$concat,
-  $elm$core$List$intersperse,
-  $elm$core$List$partition,
-  $elm$core$List$unzip,
-};
-
-export const replaceListFunctions: ts.TransformerFactory<ts.SourceFile> = (
-  context
-) => (sourceFile) => {
-  const visitor = (node: ts.Node): ts.VisitResult<ts.Node> => {
-    if (ts.isVariableStatement(node)) {
-      const name = node.declarationList.declarations[0]?.name;
-      if (isIdentifier(name) && name.text in replacements) {
-        const key = name.text as keyof typeof replacements;
-        return ast(replacements[key]);
-      }
-    }
-    return ts.visitEachChild(node, visitor, context);
-  };
-
-  return ts.visitNode(sourceFile, visitor);
-};
diff --git a/src/transforms/replaceStringFunctions.ts b/src/transforms/replaceStringFunctions.ts
deleted file mode 100644
index bd80298..0000000
--- a/src/transforms/replaceStringFunctions.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-import ts, { isIdentifier } from 'typescript';
-import { ast } from './utils/create';
-
-const $elm$core$String$join = `
-var $elm$core$String$join = F2(function (sep, strs) {
-  if (!strs.b) {
-    return "";
-  }
-  var acc = strs.a;
-  strs = strs.b;
-
-  for (; strs.b; strs = strs.b) {
-    acc = acc + sep + strs.a;
-  }
-
-  return acc;
-};
-`;
-
-
-const replacements = {
-  $elm$core$String$join,
-};
-
-export const replaceStringFunctions: ts.TransformerFactory<ts.SourceFile> = (
-  context
-) => (sourceFile) => {
-  const visitor = (node: ts.Node): ts.VisitResult<ts.Node> => {
-    if (ts.isVariableStatement(node)) {
-      const name = node.declarationList.declarations[0]?.name;
-      if (isIdentifier(name) && name.text in replacements) {
-        const key = name.text as keyof typeof replacements;
-        return ast(replacements[key]);
-      }
-    }
-    return ts.visitEachChild(node, visitor, context);
-  };
-
-  return ts.visitNode(sourceFile, visitor);
-};