diff --git a/package.json b/package.json
index b1978242ab..b9070b1012 100644
--- a/package.json
+++ b/package.json
@@ -51,7 +51,7 @@
     "mocha": "^3.0.0",
     "nyc": "^11.0.3",
     "output-file-sync": "^2.0.0",
-    "prettier": "1.7.3",
+    "prettier": "1.9.1",
     "pump": "^1.0.2",
     "rimraf": "^2.4.3",
     "semver": "^5.0.0",
diff --git a/packages/babel-core/src/config/build-config-chain.js b/packages/babel-core/src/config/build-config-chain.js
index 27d6ac99c0..00cdfab2d0 100644
--- a/packages/babel-core/src/config/build-config-chain.js
+++ b/packages/babel-core/src/config/build-config-chain.js
@@ -88,7 +88,9 @@ class ConfigChainBuilder {
   mergeConfigFile(file: ConfigFile, envName: string) {
     if (this.seenFiles.has(file)) {
       throw new Error(
-        `Cycle detected in Babel configuration file through "${file.filepath}".`,
+        `Cycle detected in Babel configuration file through "${
+          file.filepath
+        }".`,
       );
     }
 
diff --git a/packages/babel-core/src/config/option-assertions.js b/packages/babel-core/src/config/option-assertions.js
index 8cdb7a5000..facdbbf345 100644
--- a/packages/babel-core/src/config/option-assertions.js
+++ b/packages/babel-core/src/config/option-assertions.js
@@ -191,9 +191,9 @@ function assertPluginTarget(
     typeof value !== "function"
   ) {
     throw new Error(
-      `.${key}[${index}]${inArray
-        ? `[0]`
-        : ""} must be a string, object, function`,
+      `.${key}[${index}]${
+        inArray ? `[0]` : ""
+      } must be a string, object, function`,
     );
   }
   return value;
diff --git a/packages/babel-helper-fixtures/src/index.js b/packages/babel-helper-fixtures/src/index.js
index 3b664801c4..9d02acdc4c 100644
--- a/packages/babel-helper-fixtures/src/index.js
+++ b/packages/babel-helper-fixtures/src/index.js
@@ -164,7 +164,9 @@ export default function get(entryLoc): Array<Suite> {
 
         if (minimumVersion == null) {
           throw new Error(
-            `'minNodeVersion' has invalid semver format: ${taskOpts.minNodeVersion}`,
+            `'minNodeVersion' has invalid semver format: ${
+              taskOpts.minNodeVersion
+            }`,
           );
         }
 
diff --git a/packages/babel-plugin-transform-modules-amd/src/index.js b/packages/babel-plugin-transform-modules-amd/src/index.js
index 9749f35447..fe1744f4b3 100644
--- a/packages/babel-plugin-transform-modules-amd/src/index.js
+++ b/packages/babel-plugin-transform-modules-amd/src/index.js
@@ -25,16 +25,16 @@ export default function(api, options) {
           let moduleName = this.getModuleName();
           if (moduleName) moduleName = t.stringLiteral(moduleName);
 
-          const {
-            meta,
-            headers,
-          } = rewriteModuleStatementsAndPrepareHeader(path, {
-            loose,
-            strict,
-            strictMode,
-            allowTopLevelThis,
-            noInterop,
-          });
+          const { meta, headers } = rewriteModuleStatementsAndPrepareHeader(
+            path,
+            {
+              loose,
+              strict,
+              strictMode,
+              allowTopLevelThis,
+              noInterop,
+            },
+          );
 
           const amdArgs = [];
           const importNames = [];
diff --git a/packages/babel-plugin-transform-modules-commonjs/src/index.js b/packages/babel-plugin-transform-modules-commonjs/src/index.js
index b0066a9774..b6607a8144 100644
--- a/packages/babel-plugin-transform-modules-commonjs/src/index.js
+++ b/packages/babel-plugin-transform-modules-commonjs/src/index.js
@@ -113,17 +113,17 @@ export default function(api, options) {
           let moduleName = this.getModuleName();
           if (moduleName) moduleName = t.stringLiteral(moduleName);
 
-          const {
-            meta,
-            headers,
-          } = rewriteModuleStatementsAndPrepareHeader(path, {
-            exportName: "exports",
-            loose,
-            strict,
-            strictMode,
-            allowTopLevelThis,
-            noInterop,
-          });
+          const { meta, headers } = rewriteModuleStatementsAndPrepareHeader(
+            path,
+            {
+              exportName: "exports",
+              loose,
+              strict,
+              strictMode,
+              allowTopLevelThis,
+              noInterop,
+            },
+          );
 
           for (const [source, metadata] of meta.source) {
             const loadExpr = t.callExpression(t.identifier("require"), [
diff --git a/packages/babel-plugin-transform-modules-umd/src/index.js b/packages/babel-plugin-transform-modules-umd/src/index.js
index e9c249eb50..d55df24fd8 100644
--- a/packages/babel-plugin-transform-modules-umd/src/index.js
+++ b/packages/babel-plugin-transform-modules-umd/src/index.js
@@ -130,16 +130,16 @@ export default function(api, options) {
           let moduleName = this.getModuleName();
           if (moduleName) moduleName = t.stringLiteral(moduleName);
 
-          const {
-            meta,
-            headers,
-          } = rewriteModuleStatementsAndPrepareHeader(path, {
-            loose,
-            strict,
-            strictMode,
-            allowTopLevelThis,
-            noInterop,
-          });
+          const { meta, headers } = rewriteModuleStatementsAndPrepareHeader(
+            path,
+            {
+              loose,
+              strict,
+              strictMode,
+              allowTopLevelThis,
+              noInterop,
+            },
+          );
 
           const amdArgs = [];
           const commonjsArgs = [];
diff --git a/packages/babel-preset-env/scripts/build-data.js b/packages/babel-preset-env/scripts/build-data.js
index b477b8ac44..4fe5b2f191 100644
--- a/packages/babel-preset-env/scripts/build-data.js
+++ b/packages/babel-preset-env/scripts/build-data.js
@@ -54,16 +54,15 @@ const byTestSuite = suite => browser => {
     : true;
 };
 
-const compatSources = [
-  "es6",
-  "es2016plus",
-  "esnext",
-].reduce((result, source) => {
-  const data = require(`compat-table/data-${source}`);
-  data.browsers = pickBy(envs, byTestSuite(source));
-  result.push(data);
-  return result;
-}, []);
+const compatSources = ["es6", "es2016plus", "esnext"].reduce(
+  (result, source) => {
+    const data = require(`compat-table/data-${source}`);
+    data.browsers = pickBy(envs, byTestSuite(source));
+    result.push(data);
+    return result;
+  },
+  []
+);
 
 const interpolateAllResults = (rawBrowsers, tests) => {
   const interpolateResults = res => {
diff --git a/packages/babel-preset-env/src/index.js b/packages/babel-preset-env/src/index.js
index ed572ae626..dac89702d3 100644
--- a/packages/babel-preset-env/src/index.js
+++ b/packages/babel-preset-env/src/index.js
@@ -56,36 +56,36 @@ export const isPluginRequired = (
     return true;
   }
 
-  const isRequiredForEnvironments: Array<
-    string,
-  > = targetEnvironments.filter(environment => {
-    // Feature is not implemented in that environment
-    if (!plugin[environment]) {
-      return true;
-    }
+  const isRequiredForEnvironments: Array<string> = targetEnvironments.filter(
+    environment => {
+      // Feature is not implemented in that environment
+      if (!plugin[environment]) {
+        return true;
+      }
 
-    const lowestImplementedVersion: string = plugin[environment];
-    const lowestTargetedVersion: string = supportedEnvironments[environment];
-    // If targets has unreleased value as a lowest version, then don't require a plugin.
-    if (isUnreleasedVersion(lowestTargetedVersion, environment)) {
-      return false;
-      // Include plugin if it is supported in the unreleased environment, which wasn't specified in targets
-    } else if (isUnreleasedVersion(lowestImplementedVersion, environment)) {
-      return true;
-    }
+      const lowestImplementedVersion: string = plugin[environment];
+      const lowestTargetedVersion: string = supportedEnvironments[environment];
+      // If targets has unreleased value as a lowest version, then don't require a plugin.
+      if (isUnreleasedVersion(lowestTargetedVersion, environment)) {
+        return false;
+        // Include plugin if it is supported in the unreleased environment, which wasn't specified in targets
+      } else if (isUnreleasedVersion(lowestImplementedVersion, environment)) {
+        return true;
+      }
 
-    if (!semver.valid(lowestTargetedVersion)) {
-      throw new Error(
-        // eslint-disable-next-line max-len
-        `Invalid version passed for target "${environment}": "${lowestTargetedVersion}". Versions must be in semver format (major.minor.patch)`,
+      if (!semver.valid(lowestTargetedVersion)) {
+        throw new Error(
+          // eslint-disable-next-line max-len
+          `Invalid version passed for target "${environment}": "${lowestTargetedVersion}". Versions must be in semver format (major.minor.patch)`,
+        );
+      }
+
+      return semver.gt(
+        semverify(lowestImplementedVersion),
+        lowestTargetedVersion,
       );
-    }
-
-    return semver.gt(
-      semverify(lowestImplementedVersion),
-      lowestTargetedVersion,
-    );
-  });
+    },
+  );
 
   return isRequiredForEnvironments.length > 0;
 };
diff --git a/packages/babel-template/src/formatters.js b/packages/babel-template/src/formatters.js
index ccb7433112..e665e343be 100644
--- a/packages/babel-template/src/formatters.js
+++ b/packages/babel-template/src/formatters.js
@@ -37,20 +37,20 @@ export const statements: Formatter<
   Array<BabelNodeStatement>,
 > = makeStatementFormatter(body => body);
 
-export const statement: Formatter<
-  BabelNodeStatement,
-> = makeStatementFormatter(body => {
-  // We do this validation when unwrapping since the replacement process
-  // could have added or removed statements.
-  if (body.length === 0) {
-    throw new Error("Found nothing to return.");
-  }
-  if (body.length > 1) {
-    throw new Error("Found multiple statements but wanted one");
-  }
+export const statement: Formatter<BabelNodeStatement> = makeStatementFormatter(
+  body => {
+    // We do this validation when unwrapping since the replacement process
+    // could have added or removed statements.
+    if (body.length === 0) {
+      throw new Error("Found nothing to return.");
+    }
+    if (body.length > 1) {
+      throw new Error("Found multiple statements but wanted one");
+    }
 
-  return body[0];
-});
+    return body[0];
+  },
+);
 
 export const expression: Formatter<BabelNodeExpression> = {
   code: str => `(\n${str}\n)`,
diff --git a/packages/babel-template/src/populate.js b/packages/babel-template/src/populate.js
index d4fa00dec1..9f8a25f145 100644
--- a/packages/babel-template/src/populate.js
+++ b/packages/babel-template/src/populate.js
@@ -38,7 +38,9 @@ export default function populatePlaceholders(
           (replacements && replacements[placeholder.name]) || null,
         );
       } catch (e) {
-        e.message = `babel-template placeholder "${placeholder.name}": ${e.message}`;
+        e.message = `babel-template placeholder "${placeholder.name}": ${
+          e.message
+        }`;
         throw e;
       }
     });
diff --git a/packages/babel-traverse/src/index.js b/packages/babel-traverse/src/index.js
index 3b95648570..db1898f5d5 100644
--- a/packages/babel-traverse/src/index.js
+++ b/packages/babel-traverse/src/index.js
@@ -24,7 +24,9 @@ export default function traverse(
     if (parent.type !== "Program" && parent.type !== "File") {
       throw new Error(
         "You must pass a scope and parentPath unless traversing a Program/File. " +
-          `Instead of that you tried to traverse a ${parent.type} node without ` +
+          `Instead of that you tried to traverse a ${
+            parent.type
+          } node without ` +
           "passing scope and parentPath.",
       );
     }
diff --git a/packages/babel-types/src/builders/builder.js b/packages/babel-types/src/builders/builder.js
index 45c30c2f26..7458eb1c92 100644
--- a/packages/babel-types/src/builders/builder.js
+++ b/packages/babel-types/src/builders/builder.js
@@ -8,7 +8,9 @@ export default function builder(type: string, ...args: Array<any>): Object {
   const countArgs = args.length;
   if (countArgs > keys.length) {
     throw new Error(
-      `${type}: Too many arguments passed. Received ${countArgs} but can receive no more than ${keys.length}`,
+      `${type}: Too many arguments passed. Received ${countArgs} but can receive no more than ${
+        keys.length
+      }`,
     );
   }
 
diff --git a/packages/babel-types/src/definitions/utils.js b/packages/babel-types/src/definitions/utils.js
index d87826a30a..75aa6841d6 100644
--- a/packages/babel-types/src/definitions/utils.js
+++ b/packages/babel-types/src/definitions/utils.js
@@ -61,9 +61,10 @@ export function assertNodeType(...types: Array<string>): Function {
 
     if (!valid) {
       throw new TypeError(
-        `Property ${key} of ${node.type} expected node to be of a type ${JSON.stringify(
-          types,
-        )} ` + `but instead got ${JSON.stringify(val && val.type)}`,
+        `Property ${key} of ${
+          node.type
+        } expected node to be of a type ${JSON.stringify(types)} ` +
+          `but instead got ${JSON.stringify(val && val.type)}`,
       );
     }
   }
@@ -86,9 +87,10 @@ export function assertNodeOrValueType(...types: Array<string>): Function {
 
     if (!valid) {
       throw new TypeError(
-        `Property ${key} of ${node.type} expected node to be of a type ${JSON.stringify(
-          types,
-        )} ` + `but instead got ${JSON.stringify(val && val.type)}`,
+        `Property ${key} of ${
+          node.type
+        } expected node to be of a type ${JSON.stringify(types)} ` +
+          `but instead got ${JSON.stringify(val && val.type)}`,
       );
     }
   }
diff --git a/packages/babylon/src/parser/expression.js b/packages/babylon/src/parser/expression.js
index 7c0edbadac..f16bb48206 100644
--- a/packages/babylon/src/parser/expression.js
+++ b/packages/babylon/src/parser/expression.js
@@ -885,7 +885,9 @@ export default class ExpressionParser extends LValParser {
     if (node.property.name !== propertyName) {
       this.raise(
         node.property.start,
-        `The only valid meta property for ${meta.name} is ${meta.name}.${propertyName}`,
+        `The only valid meta property for ${meta.name} is ${
+          meta.name
+        }.${propertyName}`,
       );
     }
 
diff --git a/packages/babylon/src/plugins/typescript.js b/packages/babylon/src/plugins/typescript.js
index 73b185ecb5..cd9e7fc353 100644
--- a/packages/babylon/src/plugins/typescript.js
+++ b/packages/babylon/src/plugins/typescript.js
@@ -151,9 +151,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     /**
-   * If !expectSuccess, returns undefined instead of failing to parse.
-   * If expectSuccess, parseElement should always return a defined value.
-   */
+     * If !expectSuccess, returns undefined instead of failing to parse.
+     * If expectSuccess, parseElement should always return a defined value.
+     */
     tsParseDelimitedListWorker<T: N.Node>(
       kind: ParsingContext,
       parseElement: () => ?T,
diff --git a/scripts/generate-interfaces.js b/scripts/generate-interfaces.js
index 1e8864754d..9fc78bfd73 100644
--- a/scripts/generate-interfaces.js
+++ b/scripts/generate-interfaces.js
@@ -124,9 +124,9 @@ for (const type in t.NODE_FIELDS) {
 }
 
 for (let i = 0; i < t.TYPES.length; i++) {
-  let decl = `declare function is${t.TYPES[
-    i
-  ]}(node: Object, opts?: ?Object): boolean`;
+  let decl = `declare function is${
+    t.TYPES[i]
+  }(node: Object, opts?: ?Object): boolean`;
 
   if (t.NODE_FIELDS[t.TYPES[i]]) {
     decl += ` %checks (node instanceof ${NODE_PREFIX}${t.TYPES[i]})`;
diff --git a/yarn.lock b/yarn.lock
index c6a7306f2d..62ee2db133 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5059,9 +5059,9 @@ preserve@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
-prettier@1.7.3:
-  version "1.7.3"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.7.3.tgz#8e6974725273914b1c47439959dd3d3ba53664b6"
+prettier@1.9.1:
+  version "1.9.1"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.9.1.tgz#41638a0d47c1efbd1b7d5a742aaa5548eab86d70"
 
 pretty-format@^21.2.1:
   version "21.2.1"