Merge branch 'development' into fix/docLinks

* development:
  Update and standardize contracts README
  Add to CHANGELOG
  Refactor toBaseUnitAmount so that it throws if user supplies unitAmount with too many decimals
  Make assertion stricter so that one cannot submit invalid baseUnit amounts to `toUnitAmount`
  Add some missed underscores, update changelog and comments
  Add new underscore-privates rule to @0xproject/tslint-config and fix lint errors

# Conflicts:
#	packages/website/ts/pages/documentation/documentation.tsx
#	packages/website/ts/pages/shared/nested_sidebar_menu.tsx

3 files changed, 67 insertions, 0 deletions

diff --git a/packages/tslint-config/CHANGELOG.md b/packages/tslint-config/CHANGELOG.md
index 45c9eaad8..31f49eef6 100644
--- a/packages/tslint-config/CHANGELOG.md
+++ b/packages/tslint-config/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+v0.x.x - TBD
+------------------------
+    * Added custom 'underscore-privates' rule, requiring underscores to be prepended to private variable names
+    * Because our tools can be used in both a TS and JS environment, we want to make the private methods of any public facing interface show up at the bottom of auto-complete lists. Additionally, we wanted to remain consistent with respect to our usage of underscores in order to enforce this rule with a linter rule, rather then manual code reviews.
+
 v0.3.0 - _December 20, 2017_
 ------------------------
     * Added rules for unused imports, variables and Async suffixes (#265)
diff --git a/packages/tslint-config/rules/underscorePrivatesRule.ts b/packages/tslint-config/rules/underscorePrivatesRule.ts
new file mode 100644
index 000000000..472ea09ff
--- /dev/null
+++ b/packages/tslint-config/rules/underscorePrivatesRule.ts
@@ -0,0 +1,61 @@
+import * as Lint from 'tslint';
+import * as ts from 'typescript';
+
+const UNDERSCORE = '_';
+
+type RelevantClassMember =
+    | ts.MethodDeclaration
+    | ts.PropertyDeclaration
+    | ts.GetAccessorDeclaration
+    | ts.SetAccessorDeclaration;
+
+// Copied from: https://github.com/DanielRosenwasser/underscore-privates-tslint-rule
+// The version on github is not published on npm
+export class Rule extends Lint.Rules.AbstractRule {
+    public static FAILURE_STRING = 'private members must be prefixed with an underscore';
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithFunction(sourceFile, walk);
+    }
+}
+function walk(ctx: Lint.WalkContext<void>): void {
+    traverse(ctx.sourceFile);
+
+    function traverse(node: ts.Node): void {
+        checkNodeForViolations(ctx, node);
+        return ts.forEachChild(node, traverse);
+    }
+}
+function checkNodeForViolations(ctx: Lint.WalkContext<void>, node: ts.Node): void {
+    if (!isRelevantClassMember(node)) {
+        return;
+    }
+    // The declaration might have a computed property name or a numeric name.
+    const name = node.name;
+    if (!nameIsIdentifier(name)) {
+        return;
+    }
+    if (!nameStartsWithUnderscore(name.text) && memberIsPrivate(node)) {
+        ctx.addFailureAtNode(name, Rule.FAILURE_STRING);
+    }
+}
+function isRelevantClassMember(node: ts.Node): node is RelevantClassMember {
+    switch (node.kind) {
+        case ts.SyntaxKind.MethodDeclaration:
+        case ts.SyntaxKind.PropertyDeclaration:
+        case ts.SyntaxKind.GetAccessor:
+        case ts.SyntaxKind.SetAccessor:
+            return true;
+        default:
+            return false;
+    }
+}
+function nameStartsWithUnderscore(text: string) {
+    return text.charCodeAt(0) === UNDERSCORE.charCodeAt(0);
+}
+function memberIsPrivate(node: ts.Declaration) {
+    return Lint.hasModifier(node.modifiers, ts.SyntaxKind.PrivateKeyword);
+}
+function nameIsIdentifier(node: ts.Node): node is ts.Identifier {
+    return node.kind === ts.SyntaxKind.Identifier;
+}
diff --git a/packages/tslint-config/tslint.json b/packages/tslint-config/tslint.json
index acb6876c3..49e31b13d 100644
--- a/packages/tslint-config/tslint.json
+++ b/packages/tslint-config/tslint.json
@@ -81,6 +81,7 @@
     ],
     "space-within-parens": false,
     "type-literal-delimiter": true,
+    "underscore-privates": true,
     "variable-name": [true,
       "ban-keywords",
       "allow-pascal-case"